[{"_1":2,"_2086":-5,"_2087":-5},"loaderData",{"_3":4,"_1748":1749},"en-layout",{"_5":6,"_7":8},"lang","en","page",{"_9":10,"_1376":1377},"tools",{"_11":12,"_13":14,"_15":16,"_17":18,"_23":24,"_244":245,"_609":610,"_703":704,"_782":783,"_878":879,"_1343":1344},"title","Dev Toolbox","subtitle","Handy Tools for Developers","description","Dev Toolbox is a collection of browser-based tools for everyday development.","notice",{"_19":20,"_21":22},"error","Error","warning","Warning","math",{"_11":25,"_15":26,"_27":28,"_151":152},"Math Tools","Online math tools including LaTeX equation converter and binary/decimal/hex number converter.","tex",{"_11":29,"_15":30,"_31":32,"_33":34,"_35":36,"_37":38,"_39":40,"_41":42,"_43":44,"_55":56},"Online LaTeX Equation Converter","Type LaTeX expressions and preview equations in real time. 100+ math symbols with one-click input. Download as PNG, SVG, or MathML.","overview","Type LaTeX expressions and preview equations in real time. Over 100 symbols available for one-click input. Download as PNG, SVG, or MathML.","label","Type an expression:","result","Result:","download","Download","share","Share","linkCopied","Link copied","category",{"_45":46,"_47":48,"_49":50,"_51":52,"_53":54},"+/-","Math","∫","Calculus","∩","Sets","Aᵀ","Matrix","αβ","Greek","guide",{"_11":57,"_58":59,"_60":61,"_62":48,"_63":64,"_65":66,"_67":68,"_69":70,"_71":72,"_73":74,"_75":76,"_77":78,"_79":80,"_149":150},"How to Write LaTeX Math","basicTitle","Basic Formulas","basicDesc","In LaTeX, use \\frac{a}{b} for fractions, x^{2} for exponents, x_{i} for subscripts, and \\sqrt{x} for square roots. Wrap arguments in braces {}.","calculusTitle","calculusDesc","Use \\frac{dy}{dx} for derivatives, \\frac{\\partial f}{\\partial x} for partial derivatives, \\int_{a}^{b} for integrals, and \\lim_{x \\to 0} for limits.","matrixTitle","Linear Algebra","matrixDesc","Use \\vec{a} for vectors, \\begin{pmatrix} ... \\end{pmatrix} for matrices. Also supports A^{T} for transpose, A^{-1} for inverse, and \\vec{a} \\cdot \\vec{b} for dot product.","symbolsTitle","Common Greek Letters","symbolsDesc","Greek letters commonly used in math and physics can be typed with commands like \\alpha and \\theta. For uppercase, capitalize the first letter: \\Sigma.","descLabel","Description","latexCode","LaTeX Code","renderResult","Result","items",{"_81":82,"_83":84,"_85":86,"_87":88,"_89":90,"_91":92,"_93":94,"_95":96,"_97":98,"_99":100,"_101":102,"_103":104,"_105":106,"_107":108,"_109":110,"_111":112,"_113":114,"_115":116,"_117":118,"_119":120,"_121":122,"_123":124,"_125":126,"_127":128,"_129":130,"_131":132,"_133":134,"_135":136,"_137":138,"_139":140,"_141":142,"_143":144,"_145":146,"_147":148},"fraction","Fraction","exponent","Exponent","subscript","Subscript","squareRoot","Square root","bar","Bar (mean)","hat","Hat (estimate)","derivative","Derivative","partialDerivative","Partial derivative","integral","Definite integral","limit","Limit","summation","Summation","product","Product","vectorArrow","Vector (arrow)","vectorBold","Vector (bold)","dotProduct","Dot product","norm","Norm","parenMatrix","Parenthesized matrix","bracketMatrix","Bracketed matrix","inverseMatrix","Inverse matrix","transposeMatrix","Transpose matrix","alpha","Alpha","beta","Beta","gammaGamma","Gamma","deltaDelta","Delta (change)","epsilon","Epsilon","eta","Eta (learning rate)","theta","Theta","lambda","Lambda","mu","Mu (mean)","piPi","Pi","rho","Rho (density / correlation)","sigmaSigma","Sigma (std. dev. / summation)","phiPhi","Phi","omega","Omega","faqTitle","FAQ","dec2bin",{"_11":153,"_15":154,"_31":155,"_156":157,"_158":159,"_160":161,"_162":163,"_164":165,"_166":167,"_55":168,"_229":230},"Binary Converter - Decimal, Hex & Octal","Online tool to convert between binary, octal, decimal, and hexadecimal number systems. Supports 0b, 0o, and 0x prefix notation.","Enter a number and click Convert to instantly convert between different number bases. Supports 0b and 0x notation. Useful for programming and computer science studies.","button","Convert","decimal","Decimal","binary","Binary","quaternary","Quaternary","octal","Octal","hex","Hexadecimal",{"_11":169,"_170":171,"_172":173,"_174":175,"_199":200,"_204":205,"_206":207,"_208":209,"_210":211,"_149":215,"_216":217},"Understanding Number Systems","basesTitle","Number Base Comparison","basesDesc","Different number bases are used in various fields of computing and mathematics. Each base has specific advantages.","bases",[176,183,187,191,195],{"_177":178,"_179":180,"_181":182},"name","Binary (Base 2)","digits","0, 1","useCase","Hardware, digital circuits, bitwise operations",{"_177":184,"_179":185,"_181":186},"Quaternary (Base 4)","0–3","DNA encoding, some signal processing",{"_177":188,"_179":189,"_181":190},"Octal (Base 8)","0–7","Unix file permissions (chmod 755)",{"_177":192,"_179":193,"_181":194},"Decimal (Base 10)","0–9","Everyday counting, human-readable values",{"_177":196,"_179":197,"_181":198},"Hexadecimal (Base 16)","0–9, A–F","Memory addresses, color codes (#FF0000), byte representation","baseHeaders",{"_177":201,"_179":202,"_181":203},"Base","Digits","Common Use","howTitle","How Base Conversion Works","howDesc","To convert a number from one base to another, divide the number repeatedly by the target base and collect the remainders. For example, converting decimal 42 to binary: 42 ÷ 2 = 21 remainder 0, 21 ÷ 2 = 10 remainder 1, 10 ÷ 2 = 5 remainder 0, 5 ÷ 2 = 2 remainder 1, 2 ÷ 2 = 1 remainder 0, 1 ÷ 2 = 0 remainder 1. Reading the remainders bottom-up gives 101010.","tipsTitle","Quick Tips for Programmers","tips",[212,213,214],"In most programming languages, prefix 0b denotes binary (0b1010), 0o denotes octal (0o12), and 0x denotes hexadecimal (0xFF).","One hexadecimal digit represents exactly 4 binary digits (bits). For example, 0xF = 0b1111.","CSS/HTML color codes use hex: #FF5733 means R=255, G=87, B=51.","Frequently Asked Questions","faq",[218,223,226],{"_219":220,"_221":222},"q","Why do computers use binary?","a","Computers use binary because digital circuits have two states: on (1) and off (0). This maps naturally to electrical signals being high or low voltage.",{"_219":224,"_221":225},"Why is hexadecimal popular in programming?","Hexadecimal is compact (one hex digit = 4 bits) and maps neatly to binary. A byte (8 bits) is exactly 2 hex digits, making memory addresses and byte values easy to read.",{"_219":227,"_221":228},"What is the largest number I can convert?","This tool handles JavaScript's safe integer range (up to 2^53 - 1, or 9,007,199,254,740,991). For most practical purposes, this is more than sufficient.","glossary",[231,235,238,241],{"_11":232,"_233":234},"Bit","body","A bit (binary digit) is the smallest unit of data in computing. It can hold a value of either 0 or 1. Eight bits make one byte.",{"_11":236,"_233":237},"Byte","A byte consists of 8 bits and can represent values from 0 to 255 (or 0x00 to 0xFF in hexadecimal). It is the fundamental unit of data storage.",{"_11":239,"_233":240},"Radix (Base)","The radix, or base, of a number system determines how many unique digits are used. For example, base 10 uses digits 0–9, while base 16 uses 0–9 and A–F.",{"_11":242,"_233":243},"Two's Complement","Two's complement is the most common method for representing signed integers in binary. The most significant bit indicates the sign: 0 for positive, 1 for negative.","text",{"_11":246,"_15":247,"_248":249,"_271":272,"_370":371,"_442":443,"_527":528},"Text Tools","Online text tools including JSON formatter, URL encoder/decoder, JSON diff, and XML pretty printer.","urlencode",{"_11":250,"_15":251,"_31":252,"_33":253,"_254":255,"_156":256,"_35":36,"_229":261},"URL Encoder & Decoder","Online tool to encode and decode URLs (percent-encoding) instantly. Supports Unicode and special characters.","Enter text and press the Encode or Decode button to convert. Supports Japanese and special character encoding.","Type the text to encode/decode:","placeholder","",{"_257":258,"_259":260},"encode","Encode","decode","Decode",[262,265,268],{"_11":263,"_233":264},"URL Encode (Percent-encoding)","URL encoding (also known as percent encoding) is a technique for converting characters that are either not allowed in URLs or have special meanings into a format that can be safely transmitted.",{"_11":266,"_233":267},"Characters to be encoded","Characters to be encoded include symbols (such as :, /, ?, #, [, ], @, etc.), reserved characters with special meanings, and non-ASCII characters (such as Japanese or other multilingual characters) that cannot be used directly in URLs.",{"_11":269,"_233":270},"Encoding Method","The general encoding method involves first converting the target characters into their byte representation using UTF-8, then converting each byte into its hexadecimal form, and finally prefixing each hex value with a '%' symbol. For example, the Japanese character 'あ' becomes '%E3%81%82'.","json",{"_11":273,"_15":274,"_31":275,"_33":276,"_156":277,"_278":279,"_280":281,"_282":283,"_284":285,"_286":20,"_35":36,"_55":287,"_229":354},"JSON Formatter & Validator","Online JSON formatter, minifier, and validator with syntax highlighting. Format, compress, sort keys, and validate JSON with detailed error messages.","Paste a JSON string and click Format to get a nicely indented and highlighted output. Use Minify to compress, or Sort Keys to alphabetize object keys. Includes validation, detailed error messages, and syntax highlighting — ideal for API development and debugging.","Type the JSON text to format:","Format","minifyButton","Minify","copyButton","Copy","copiedMessage","Copied!","sortKeysLabel","Sort keys","errorLabel",{"_11":288,"_289":290,"_291":292,"_293":294,"_301":302,"_325":326,"_327":328,"_329":330,"_208":335,"_210":336,"_149":215,"_216":341},"JSON Format Guide","syntaxTitle","JSON Syntax Reference","syntaxDesc","JSON (JavaScript Object Notation) supports six data types. All JSON data must be one of these types, and strings must use double quotes.","syntaxHeaders",{"_295":296,"_297":298,"_299":300},"type","Type","syntax","Syntax","example","Example","syntaxItems",[303,307,311,315,318,322],{"_295":304,"_297":305,"_299":306},"Object","{ \"key\": value }","{ \"name\": \"John\" }",{"_295":308,"_297":309,"_299":310},"Array","[ value, ... ]","[1, 2, 3]",{"_295":312,"_297":313,"_299":314},"String","\"text\"","\"hello\"",{"_295":316,"_297":179,"_299":317},"Number","42, 3.14",{"_295":319,"_297":320,"_299":321},"Boolean","true / false","true",{"_295":323,"_297":324,"_299":324},"Null","null","useCasesTitle","Common Use Cases","useCasesDesc","JSON formatting and validation is essential across many development workflows.","useCases",[331,332,333,334],"API development — Inspect and debug API responses by formatting raw JSON payloads.","Configuration files — Format package.json, tsconfig.json, and other config files for readability.","Data transformation — Verify the output of CSV-to-JSON or XML-to-JSON conversions.","Log analysis — Pretty-print structured JSON logs for easier debugging.","Tips",[337,338,339,340],"Use Minify to strip whitespace and reduce file size for production deployments.","Sort Keys alphabetizes object keys, making JSON easier to compare with diff tools.","Error messages show the position of syntax errors so you can fix them quickly.","Trailing commas are invalid in JSON (unlike JavaScript) — remove them before formatting.",[342,345,348,351],{"_219":343,"_221":344},"Is my data safe when using this tool?","Yes. All processing is done entirely in your browser using JavaScript. Your JSON data is never sent to any server.",{"_219":346,"_221":347},"What is the difference between Format and Minify?","Format adds indentation and line breaks for readability. Minify removes all unnecessary whitespace to produce the most compact representation, which is useful for reducing payload size.",{"_219":349,"_221":350},"Why do I get a trailing comma error?","The JSON specification (RFC 8259) does not allow trailing commas after the last element in an object or array. While JavaScript allows them, you must remove trailing commas for valid JSON.",{"_219":352,"_221":353},"Does Sort Keys change array order?","No. Sort Keys only reorders object keys alphabetically. Array element order is preserved because order is significant in JSON arrays.",[355,358,361,364,367],{"_11":356,"_233":357},"JSON (JavaScript Object Notation)","A lightweight, text-based data interchange format derived from JavaScript. It is language-independent and widely used for APIs, configuration files, and data storage. Defined by RFC 8259.",{"_11":359,"_233":360},"JSON Schema","A vocabulary for annotating and validating JSON documents. It defines the structure, data types, and constraints of JSON data, enabling automated validation of API requests and responses.",{"_11":362,"_233":363},"RFC 8259","The IETF standard that defines the JSON data interchange format. It specifies syntax rules such as requiring double quotes for strings and prohibiting trailing commas.",{"_11":365,"_233":366},"Minification","The process of removing all unnecessary whitespace, line breaks, and indentation from JSON (or other code) to reduce file size. Minified JSON is functionally identical to formatted JSON.",{"_11":368,"_233":369},"Trailing Comma","A comma placed after the last element in an object or array. While allowed in JavaScript and some other languages, trailing commas are invalid in the JSON specification and will cause a parse error.","jsonDiff",{"_11":372,"_15":373,"_31":374,"_33":276,"_156":375,"_35":36,"_55":376,"_229":427},"JSON Diff - Compare & Visualize Differences","Online tool to compare two JSON objects and visualize differences. Spot changes in API responses, config files, and database records.","Enter two JSON objects and click Compare to see the differences highlighted. Useful for comparing API responses and verifying configuration changes.","Compare",{"_11":377,"_378":379,"_380":381,"_382":383,"_399":400,"_325":326,"_327":404,"_329":405,"_208":410,"_411":412,"_210":413,"_149":215,"_216":418},"Understanding JSON Diff","readingTitle","How to Read the Diff Results","readingDesc","The diff output uses symbols and colors to indicate what changed between the two JSON documents.","diffTypes",[384,391,395],{"_385":386,"_387":388,"_389":390},"symbol","+ (green)","operation","ADD","meaning","A new key or value exists in the second JSON that is not in the first.",{"_385":392,"_387":393,"_389":394},"- (red)","REMOVE","A key or value exists in the first JSON but not in the second.",{"_385":396,"_387":397,"_389":398},"- / + (red then green)","UPDATE","A value changed — the old value is shown in red and the new value in green.","diffTypeHeaders",{"_385":401,"_387":402,"_389":403},"Symbol","Operation","Meaning","JSON diff comparison is essential for developers working with structured data.",[406,407,408,409],"API response comparison — Compare responses from different API versions or environments to spot breaking changes.","Config file changes — Verify configuration differences between staging and production environments.","Data migration validation — Ensure data integrity by comparing records before and after migration.","Code review — Quickly identify what changed in JSON-based fixtures, mocks, or test data.","Tips for Accurate Comparison","tipsDesc","Follow these tips to get the most accurate diff results. The tool automatically formats your JSON before comparing, but proper input helps you interpret results more easily.",[414,415,416,417],"Ensure both inputs are valid JSON — the tool will show a syntax error if parsing fails.","Key order does not affect the diff — only values and structural differences are detected.","Arrays are compared by index — reordering array elements will show as changes.","Nested objects are compared recursively — differences at any depth level are detected.",[419,421,424],{"_219":343,"_221":420},"Yes. All comparison is performed entirely in your browser using JavaScript. Your JSON data is never sent to any server.",{"_219":422,"_221":423},"Does key order matter in the comparison?","No. JSON objects are unordered by specification, so {\"a\":1,\"b\":2} and {\"b\":2,\"a\":1} are considered identical. Only actual value differences are shown.",{"_219":425,"_221":426},"Can I compare JSON arrays?","Yes. You can compare JSON arrays as well as objects. Arrays are compared element by element based on their index position.",[428,431,434,437,440],{"_11":429,"_233":430},"Learn about JSON","JSON stands for JavaScript Object Notation and is a lightweight data interchange format. It is a text-based data format that is used to exchange data between different computer systems, applications and programming languages.",{"_11":432,"_233":433},"JSONPath","JSONPath is a query language for JSON, similar to XPath for XML. It allows you to select and extract specific elements from a JSON document using path expressions like $.store.book[0].title.",{"_11":435,"_233":436},"Diff Algorithm","A diff algorithm computes the minimum set of changes needed to transform one data structure into another. For JSON, this involves recursively comparing objects and arrays to detect additions, removals, and value updates at every level of nesting.",{"_11":438,"_233":439},"Nested Object","A nested object is a JSON object contained within another object as a value. For example, {\"user\": {\"name\": \"Alice\"}} has a nested object. JSON diff tools compare nested structures recursively to detect changes at any depth.",{"_11":359,"_233":441},"JSON Schema is a vocabulary for annotating and validating JSON documents. It defines the expected structure, data types, and constraints of a JSON document, making it useful for API contract validation and data quality assurance.","xml",{"_11":444,"_15":445,"_31":446,"_33":447,"_448":449,"_450":451,"_452":453,"_454":455,"_156":277,"_278":279,"_35":36,"_280":281,"_282":283,"_55":456,"_229":511},"XML Formatter - Pretty Print XML","Format compressed XML and SVG in your browser. Indent with two spaces, four spaces or a tab, or minify it back down to a single line.","Format compressed XML and SVG in your browser. Indent with two spaces, four spaces or a tab, or minify it back down to a single line. Syntax highlighting makes structure easy to read at a glance. Ideal for debugging API responses and data integrations.","Type the XML document to format:","indentLabel","Indent","indentTwo","2 spaces","indentFour","4 spaces","indentTab","Tab",{"_11":457,"_289":458,"_291":459,"_293":460,"_301":463,"_325":326,"_327":488,"_329":489,"_208":335,"_210":494,"_149":215,"_216":499},"XML Format Guide","XML Syntax Reference","XML (Extensible Markup Language) uses a tree structure of nested elements. Every XML document must have exactly one root element, and all tags must be properly closed.",{"_461":462,"_297":298,"_299":300},"construct","Construct",[464,468,472,476,480,484],{"_461":465,"_297":466,"_299":467},"Element","content","Alice",{"_461":469,"_297":470,"_299":471},"Attribute","","",{"_461":473,"_297":474,"_299":475},"Self-closing","","
",{"_461":477,"_297":478,"_299":479},"Comment","","",{"_461":481,"_297":482,"_299":483},"CDATA","","",{"_461":485,"_297":486,"_299":487},"Declaration","","","XML formatting is useful in many development and data exchange scenarios.",[490,491,492,493],"API debugging — Inspect and format SOAP/REST XML responses for easier analysis.","Configuration files — Format Maven pom.xml, Spring beans, and other config files for readability.","Data interchange — Verify XML exports from databases, spreadsheets, or enterprise systems.","SVG editing — Pretty-print SVG graphics files to understand and modify their structure.",[495,496,497,498],"XML is case-sensitive — and are different elements.","Attribute values must always be quoted with single or double quotes.","Special characters like <, >, and & must be escaped as <, >, and & in text content.","Use CDATA sections to include blocks of text that contain many special characters without escaping.",[500,502,505,508],{"_219":343,"_221":501},"Yes. All processing is done entirely in your browser using JavaScript. Your XML data is never sent to any server.",{"_219":503,"_221":504},"What is the difference between XML and HTML?","XML is a strict, extensible markup language for data representation, while HTML is designed for displaying web pages. XML requires all tags to be closed and is case-sensitive, whereas HTML is more lenient.",{"_219":506,"_221":507},"Can this tool validate XML?","This tool checks for well-formedness (proper nesting and closing of tags). It does not validate against an XML Schema (XSD) or DTD.",{"_219":509,"_221":510},"What indentation does the formatter use?","The formatter uses 2-space indentation by default, which is the most common convention for XML documents.",[512,515,518,521,524],{"_11":513,"_233":514},"XML (Extensible Markup Language)","A markup language for encoding documents in a human-readable and machine-readable format. XML is a W3C standard widely used for data interchange between systems, configuration files, and document formats like SVG and XHTML.",{"_11":516,"_233":517},"Well-formed XML","An XML document that follows all syntax rules: it has exactly one root element, all tags are properly nested and closed, attribute values are quoted, and element names are case-sensitive. A well-formed document can be parsed by any XML parser.",{"_11":519,"_233":520},"XML Schema (XSD)","A W3C standard for defining the structure, content, and data types of XML documents. Unlike DTD, XSD itself is written in XML and supports data types, namespaces, and complex type definitions.",{"_11":522,"_233":523},"Namespace","A mechanism to avoid element name conflicts by qualifying names with a URI. Declared using the xmlns attribute (e.g., xmlns:xsl=\"http://www.w3.org/1999/XSL/Transform\"), namespaces enable combining elements from different vocabularies in a single document.",{"_11":525,"_233":526},"XSLT","Extensible Stylesheet Language Transformations (XSLT) is a language for transforming XML documents into other formats such as HTML, plain text, or different XML structures. It uses template rules to match and process elements.","charCounter",{"_11":529,"_15":530,"_31":531,"_33":532,"_254":533,"_156":534,"_535":536,"_35":537,"_55":553},"Character Counter & Word Counter","Count characters, words, sentences, lines, and paragraphs in real time. Supports with/without spaces. Ideal for social media posts, essays, SEO meta tags, and content writing.","Type or paste text to instantly see character count, line count, paragraph count, and more. Toggle between including or excluding spaces. Useful for reports, social media posts, and SEO meta tag checks.","Enter text:","Type or paste your text here","Count","resetButton","Reset",{"_538":539,"_540":541,"_542":543,"_544":255,"_545":546,"_547":548,"_549":550,"_551":552},"charsWithSpaces","Characters (with spaces)","charsWithoutSpaces","Characters (without spaces)","words","Words","wordsNote","sentences","Sentences","lines","Lines","paragraphs","Paragraphs","manuscriptPages","Manuscript pages",{"_11":554,"_555":556,"_557":558,"_559":560,"_566":567,"_325":326,"_327":592,"_329":593,"_149":215,"_216":599},"Character Count Guide","limitsTitle","Character Limits by Platform","limitsDesc","Many platforms enforce character limits. Here are the key limits you should know.","limitsHeaders",{"_561":562,"_563":564,"_99":565},"service","Service","field","Field","Character Limit","limits",[568,572,576,579,583,585,589],{"_561":569,"_563":570,"_99":571},"X (Twitter)","Post","280 characters (CJK: 140)",{"_561":573,"_563":574,"_99":575},"Instagram","Caption","2,200 characters",{"_561":573,"_563":577,"_99":578},"Profile bio","150 characters",{"_561":580,"_563":581,"_99":582},"YouTube","Title","100 characters",{"_561":580,"_563":74,"_99":584},"5,000 characters",{"_561":586,"_563":587,"_99":588},"Google Search","Title tag","Approx. 60 characters",{"_561":586,"_563":590,"_99":591},"Meta description","Approx. 160 characters","Here are typical scenarios where character counting is essential.",[594,595,596,597,598],"Writing articles or essays with specific word or character requirements","Creating ad copy that must fit within character limits","Checking SEO title tags and meta descriptions for optimal length","Tracking essay or report length for academic submissions","Ensuring social media posts fit within platform character limits",[600,603,606],{"_219":601,"_221":602},"Are spaces included in the character count?","\"Characters (with spaces)\" includes all whitespace, while \"Characters (without spaces)\" excludes spaces, tabs, and line breaks. Choose the metric that fits your needs.",{"_219":604,"_221":605},"Is my text sent to a server?","No, all processing happens in your browser. Your text is never sent to any server.",{"_219":607,"_221":608},"How is manuscript page count calculated?","Based on the Japanese 400-character manuscript paper (genkō yōshi). The character count is divided by 400 to estimate the number of pages.","coding",{"_11":611,"_15":612,"_613":614},"Coding Tools","Online coding tools including Scheme playground for running Lisp code in your browser.","scheme",{"_11":615,"_15":616,"_31":617,"_33":618,"_156":619,"_35":36,"_55":620,"_229":684},"Scheme Playground - Online IDE","Run Scheme (Lisp) code instantly in your browser. Great for SICP exercises, lambda calculus, and learning functional programming.","Type your Scheme code and click Run to see the output instantly. Perfect for SICP (Structure and Interpretation of Computer Programs) exercises and lambda calculus learning.","Type the code:","Run",{"_11":621,"_622":623,"_624":625,"_626":627,"_658":659,"_660":661,"_662":663,"_664":665,"_149":215,"_216":671},"Scheme Programming Guide","basicsTitle","Basic Syntax","basicsDesc","Scheme uses prefix notation (also called Polish notation) where the operator comes before the operands, all wrapped in parentheses.","examples",[628,634,638,642,646,650,654],{"_11":629,"_630":631,"_632":633},"Arithmetic","code","(+ 1 2 3) ; => 6\n(* 4 5) ; => 20\n(- 10 3) ; => 7\n(/ 15 3) ; => 5","desc","Basic math operations. Operators can take multiple arguments.",{"_11":635,"_630":636,"_632":637},"Variables","(define x 42)\n(define name \"hello\")\nx ; => 42","Use define to bind values to names.",{"_11":639,"_630":640,"_632":641},"Functions","(define (square x)\n (* x x))\n(square 5) ; => 25","Define functions with (define (name args...) body).",{"_11":643,"_630":644,"_632":645},"Conditionals","(if (> 3 2)\n \"yes\"\n \"no\") ; => \"yes\"\n\n(cond\n ((< x 0) \"negative\")\n ((= x 0) \"zero\")\n (else \"positive\"))","Use if for simple conditions, cond for multiple branches.",{"_11":647,"_630":648,"_632":649},"Lists","(list 1 2 3) ; => (1 2 3)\n(car '(1 2 3)) ; => 1\n(cdr '(1 2 3)) ; => (2 3)\n(cons 0 '(1 2)) ; => (0 1 2)","Lists are the fundamental data structure. car returns the first element, cdr returns the rest.",{"_11":651,"_630":652,"_632":653},"Lambda (Anonymous Functions)","; Anonymous function\n((lambda (x) (* x x)) 5) ; => 25\n\n; Assign lambda to variable\n(define double\n (lambda (x) (* x 2)))\n(double 7) ; => 14\n\n; Higher-order function\n(map (lambda (x) (+ x 1))\n '(1 2 3)) ; => (2 3 4)","Lambda creates unnamed functions. Essential for functional programming patterns like map and filter.",{"_11":655,"_630":656,"_632":657},"Recursion","(define (fibonacci n)\n (if (<= n 1)\n n\n (+ (fibonacci (- n 1))\n (fibonacci (- n 2)))))\n(fibonacci 10) ; => 55","Scheme relies heavily on recursion instead of loops.","examplesTitle","Code Examples","examplesDesc","Try these examples in the playground above. Click Run to see the results.","conceptsTitle","Key Concepts","concepts",[666,667,668,669,670],"Everything is an expression — Every piece of Scheme code returns a value, including if statements and definitions.","First-class functions — Functions can be passed as arguments, returned from other functions, and stored in variables.","Tail call optimization — Scheme guarantees that tail-recursive functions run in constant stack space, making recursion as efficient as loops.","Lexical scoping — Variables are resolved in the environment where they are defined, not where they are called.","Minimalist design — Scheme has very few special forms. Most functionality is built from a small set of primitives.",[672,675,678,681],{"_219":673,"_221":674},"What is the difference between Scheme and Common Lisp?","Scheme is minimalist with a single namespace and guaranteed tail call optimization. Common Lisp is larger with separate namespaces for functions and variables, and a more extensive standard library. Scheme emphasizes elegance and simplicity.",{"_219":676,"_221":677},"Why are there so many parentheses?","Parentheses in Scheme define the structure of the code (S-expressions). This uniform syntax makes the language easy to parse and enables powerful metaprogramming with macros. Most editors provide auto-matching to make them manageable.",{"_219":679,"_221":680},"Is Scheme still used today?","Yes. Scheme is widely used in computer science education (e.g., the classic textbook SICP). Languages like Racket (a Scheme descendant) are actively developed. Guile Scheme is used as an extension language in GNU software.",{"_219":682,"_221":683},"Does the code run on a server?","No. All code runs entirely in your browser using the LIPS Scheme interpreter (JavaScript-based). Nothing is sent to any server.",[685,688,691,693,696,700],{"_11":686,"_233":687},"Scheme","Scheme is a classic programming language in the Lisp family, created in 1975 by Guy L. Steele and Gerald Jay Sussman at MIT. It is known for its clean, minimalist design and is widely used in computer science education.",{"_11":689,"_233":690},"S-expression","An S-expression (symbolic expression) is the basic syntax unit in Lisp languages. It is either an atom (like a number or symbol) or a list of S-expressions enclosed in parentheses, such as (+ 1 2).",{"_11":136,"_233":692},"Lambda creates an anonymous (unnamed) function. For example, (lambda (x) (* x x)) creates a function that squares its argument. The name comes from lambda calculus, the mathematical foundation of functional programming.",{"_11":694,"_233":695},"Tail Call Optimization","Tail call optimization (TCO) is a technique where the compiler/interpreter reuses the current stack frame for a function call in tail position. This allows recursive functions to run without growing the call stack, preventing stack overflow errors.",{"_11":697,"_233":698,"_699":-7},"SICP","Structure and Interpretation of Computer Programs is a legendary textbook by Harold Abelson and Gerald Jay Sussman. Originally used at MIT, it teaches fundamental programming concepts using Scheme and is freely available online.","link",{"_11":701,"_233":702},"LIPS Interpreter","This playground uses LIPS (Lisp In Parentheses Syntax), a Scheme interpreter written in JavaScript. It supports most R7RS Scheme features and runs entirely in the browser.","network",{"_11":705,"_15":706,"_707":708},"Network Tools","Online network tools including IP address checker with geolocation map display.","ipLocation",{"_11":709,"_15":710,"_31":710,"_55":711,"_229":769},"IP Address & Location Checker","Automatically detects your IP address and approximate location, displayed on an interactive map. Supports IPv4/IPv6. Useful for network diagnostics and privacy checks.",{"_11":712,"_713":714,"_715":716,"_717":718,"_732":733,"_738":739,"_740":741,"_742":743,"_744":745,"_746":747,"_752":753,"_325":326,"_329":754,"_149":215,"_216":759},"Understanding IP Addresses","versionsTitle","IPv4 vs IPv6","versionsDesc","There are two versions of the Internet Protocol in use today.","versions",[719,727],{"_177":720,"_721":722,"_723":724,"_725":726},"IPv4","format","192.168.1.1","addressSpace","About 4.3 billion addresses","status","Most widely used, but addresses are exhausted",{"_177":728,"_721":729,"_723":730,"_725":731},"IPv6","2001:0db8:85a3::8a2e:0370:7334","Virtually unlimited (3.4×10^38)","Gradually being adopted worldwide","versionHeaders",{"_177":734,"_721":735,"_723":736,"_725":737},"Version","Format Example","Address Space","Status","whatIsTitle","What Does Your IP Address Reveal?","whatIsDesc","Your IP address can reveal your approximate geographic location, Internet Service Provider (ISP), and the type of network you are using. However, it does not reveal your exact street address or personal identity.","howItWorksTitle","How IP Geolocation Works","howItWorksDesc","IP addresses are not assigned randomly — they are managed in blocks by region and ISP. This structure makes it possible to estimate an approximate location.","howItWorksSteps",[748,749,750,751],"IANA allocates large IP address blocks to regional registries (APNIC, ARIN, etc.)","Regional registries distribute address blocks to ISPs and organizations in each country","ISPs assign IP addresses to subscribers — at this point, the region and ISP are determined","Geolocation databases collect this allocation data and map IP addresses to locations","howItWorksNote","Because of this, accuracy is limited to the city level at best. Using a VPN or proxy will show a different location than your actual one.",[755,756,757,758],"VPN verification — Confirm your VPN is working by checking if your IP address has changed.","Troubleshooting — Diagnose network issues by identifying your public IP and ISP information.","Geolocation testing — Verify how websites and services detect your location.","Security audits — Check what information your IP address exposes to the internet.",[760,763,766],{"_219":761,"_221":762},"Why does the location shown not match my exact location?","IP geolocation is approximate and typically accurate to the city or region level. Your ISP may route your traffic through a nearby data center, so the displayed location may be the ISP's facility rather than your home.",{"_219":764,"_221":765},"What is the difference between a public and private IP address?","A public IP address is assigned by your ISP and is visible on the internet. Private IP addresses (like 192.168.x.x or 10.x.x.x) are used within your local network and are not directly accessible from the internet.",{"_219":767,"_221":768},"Can someone find my exact location from my IP address?","No. IP geolocation only provides an approximate location, usually at the city level. Only your ISP can map your IP to your physical address, and they are legally required to protect that information.",[770,773,776,779],{"_11":771,"_233":772},"IP Address","An Internet Protocol (IP) address is a numerical label assigned to each device connected to a network. It serves two main purposes: identifying the host and providing the location of the host in the network.",{"_11":774,"_233":775},"ISP (Internet Service Provider)","An ISP is a company that provides internet access to customers. Your ISP assigns your public IP address and can see your internet traffic unless it is encrypted.",{"_11":777,"_233":778},"AS Number (ASN)","An Autonomous System Number identifies a network or group of networks under a single administrative entity. ISPs and large organizations each have their own ASN.",{"_11":780,"_233":781},"Geolocation","IP geolocation is the process of determining the geographic location of a device based on its IP address. Accuracy varies from country-level to city-level depending on the database used.","security",{"_11":784,"_15":785,"_786":787,"_863":864},"Security Tools","Online security tools including SHA hash generator and AI-powered file type detector.","hash",{"_11":788,"_15":789,"_31":790,"_791":792,"_793":794,"_156":795,"_55":796,"_229":848},"SHA Hash Generator (SHA1/SHA256/SHA512)","Generate SHA1, SHA256, SHA384, and SHA512 hash values online. Supports HMAC. All processing happens in your browser for maximum security.","Supports SHA1, SHA256, SHA384, SHA512, and HMAC generation. All hash generation is performed in your browser — your data is never sent to a server or stored anywhere.","label1","Type the text to generate:","label2","HMAC(Optional):","Generate",{"_11":797,"_798":799,"_800":801,"_802":803,"_823":824,"_325":326,"_327":829,"_329":830,"_835":836,"_837":838,"_149":215,"_216":839},"Understanding Hash Functions","algorithmTitle","Algorithm Comparison","algorithmDesc","SHA family algorithms differ in output length, security level, and performance. Choose the right algorithm for your use case.","algorithms",[804,810,815,819],{"_177":805,"_806":807,"_782":808,"_181":809},"SHA-1","output","160 bits (40 hex)","Deprecated","Legacy systems only",{"_177":811,"_806":812,"_782":813,"_181":814},"SHA-256","256 bits (64 hex)","Secure","Digital signatures, SSL/TLS, Bitcoin",{"_177":816,"_806":817,"_782":813,"_181":818},"SHA-384","384 bits (96 hex)","Government, high-security applications",{"_177":820,"_806":821,"_782":813,"_181":822},"SHA-512","512 bits (128 hex)","Maximum security, large data integrity","algorithmHeaders",{"_177":825,"_806":826,"_782":827,"_181":828},"Algorithm","Output Length","Security","Use Case","Hash functions are fundamental to modern security and data integrity verification.",[831,832,833,834],"Password storage — Store hashed passwords instead of plain text for secure authentication.","File integrity — Verify downloaded files have not been corrupted or tampered with by comparing checksums.","Digital signatures — Hash the message before signing to ensure authenticity and integrity.","Data deduplication — Identify duplicate data blocks using their hash values for efficient storage.","hmacTitle","What is HMAC?","hmacDesc","HMAC (Hash-based Message Authentication Code) combines a hash function with a secret key to verify both data integrity and authenticity. Unlike a simple hash, HMAC ensures the message was sent by someone who possesses the secret key. It is widely used in API authentication, JWT tokens, and secure communication protocols.",[840,843,845],{"_219":841,"_221":842},"What is the difference between SHA-256 and SHA-512?","SHA-256 produces a 256-bit hash and SHA-512 produces a 512-bit hash. SHA-512 provides stronger security but SHA-256 is sufficient for most applications. On 64-bit systems, SHA-512 can actually be faster than SHA-256.",{"_219":343,"_221":844},"Yes. All hash generation is performed entirely in your browser using the Web Crypto API. Your data is never sent to any server.",{"_219":846,"_221":847},"Can a hash be reversed to get the original text?","No. Hash functions are one-way — it is computationally infeasible to reverse a hash back to its original input. This is what makes them useful for password storage.",[849,852,854,857,860],{"_11":850,"_233":851},"SHA (Secure Hash Algorithm)","The Secure Hash Algorithm (SHA), abbreviated as SHA, is also known as a cryptographic hash function. It has been designated as the standard hash function, Secure Hash Standard, by the National Institute of Standards and Technology (NIST) in the United States. SHA transforms any large data block into a fixed-size output (typically much shorter than the input).",{"_11":22,"_233":853},"SHA-1 is now considered vulnerable and should not be used for cryptographic applications.",{"_11":855,"_233":856},"Hash Collision","A hash collision occurs when two different inputs produce the same hash output. Modern algorithms like SHA-256 are designed to make collisions extremely unlikely — the probability is approximately 1 in 2^128.",{"_11":858,"_233":859},"Salt","A salt is random data added to the input of a hash function before hashing. It prevents attackers from using precomputed tables (rainbow tables) to crack password hashes. Each password should have a unique salt.",{"_11":861,"_233":862},"HMAC (Hash-based Message Authentication Code)","HMAC is a mechanism for calculating a message authentication code using a hash function combined with a secret key. It provides both data integrity and authentication, ensuring that the message has not been altered and was sent by someone with the key.","fileScanner",{"_11":865,"_15":866,"_31":867,"_156":868,"_869":870,"_229":871},"File Type Detector - Dr.Filescan","Detect file types using AI-powered analysis by Google Magika. All processing happens in your browser — files are never uploaded.","Drop files to detect their types. Powered by Google's Magika AI. All processing happens in your browser — files are never uploaded anywhere.","Scan file(s)","scanError","The file could not be identified.",[872,875],{"_11":873,"_233":874},"Lean about Magika","Magika is a tool to detect common file content types, using deep learning. View project on “https://securityresearch.google/magika/introduction/overview”.",{"_11":876,"_233":877},"Disclaimer","The service provider has no affiliation with the developers or organizations behind Magika and is solely using it for the purpose of library validation. This service is intended for validating Magika and is not designed for detecting malware in files. The results of file scans are indicative and do not guarantee their accuracy.","geo",{"_11":880,"_15":881,"_882":883,"_1057":1058,"_1151":1152,"_1239":1240},"GIS & Geography Tools","Online GIS tools: WKT/GeoJSON converter & viewer, SHP to GeoJSON converter, and Geocode map viewer. All browser-based.","geojsonViewer",{"_11":884,"_15":885,"_31":886,"_33":887,"_156":892,"_895":896,"_897":898,"_899":900,"_901":902,"_903":904,"_905":906,"_907":908,"_909":910,"_286":20,"_947":948,"_55":949,"_229":1044},"GeoJSON Viewer & Validator","View and validate GeoJSON on a map. Checks winding order, ring closure, coordinate ranges and the declared bbox. Everything runs in your browser.","Draws GeoJSON on a map and validates it against RFC 7946. It checks ring closure, winding order and coordinate ranges, and whether a declared bbox still matches the data. Everything runs in your browser.",{"_888":889,"_890":891},"geojson","GeoJSON","properties","Properties",{"_893":894},"view","View GeoJSON","propertiesHint","Click a shape on the map to see the properties of that feature.","propertiesEmpty","No properties. A bare geometry cannot carry them — wrap it in a Feature and add a \"properties\" member to attach attributes.","bboxNote","The orange dashed rectangle is the bbox declared in the GeoJSON.","issueErrorLabel","Does not conform to RFC 7946","issueWarningLabel","Worth checking","issueDrawNote","Nothing is drawn because the data does not conform to the specification. Fix the issues above and try again.","issuesTruncated","and {count} more","issues",{"_911":912,"_913":914,"_915":916,"_917":918,"_919":920,"_921":922,"_923":924,"_925":926,"_927":928,"_929":930,"_931":932,"_933":934,"_935":936,"_937":938,"_939":940,"_941":942,"_943":944,"_945":946},"outOfRange","Coordinates are outside the valid range. Longitude must be within ±180 and latitude within ±90. GeoJSON writes positions as [longitude, latitude], so check whether longitude and latitude have been swapped.","badPosition","A position is not a valid array of numbers. Every position needs at least two finite numbers, written as [longitude, latitude]. Empty arrays, a single number, numbers written as strings, and entries that are not arrays at all trigger this.","badAltitude","The third element of a position is not a number. A position may carry an altitude as an optional third element, but it has to be a finite number. The first two values are still usable, so the shape is drawn.","unknownType","This \"type\" is not valid here. Only Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon and GeometryCollection are geometry types, and every entry in \"features\" has to be a Feature. Case matters too: \"point\" is not \"Point\". Unrecognized types are not drawn.","badBbox","The bbox cannot be read. It needs four numbers (six for 3D data), all finite and within longitude ±180 and latitude ±90.","invertedBbox","The bbox has south and north the wrong way round. The second value is the southern edge and the fourth is the northern one, so the second has to be the smaller of the two. A western value larger than the eastern one is fine — that is how a bbox crossing the antimeridian is written.","badDepth","The nesting of \"coordinates\" does not match the geometry type, or it is uneven between branches.","missingField","A required member is missing. Every geometry needs \"type\" and \"coordinates\"; a Feature also needs \"geometry\" and \"properties\".","badProperties","A Feature needs a \"properties\" member whose value is a JSON object or null. Attributes cannot be attached without it. The geometry is still drawn.","badId","A Feature \"id\" has to be a string or a number.","mixedPropertyType","This property holds values of different types across features — a number in some, a string in others. Sorting, filtering and aggregation all stop working consistently once that happens, and it is easy to introduce when the data came from a CSV. The path points at the first feature where the type changes. Values of null are ignored, since null is how an absent value is normally written.","unclosedRing","The ring is not closed. The first and last positions have to hold identical values — including the altitude, if one is present.","shortRing","The ring has too few positions. A polygon ring needs four or more, with the first and last positions identical. Since the ring encloses no area, it is not drawn on the map.","shortLine","The line does not have enough positions. A LineString needs two or more.","windingOrder","The ring does not follow the right-hand rule. Outer rings should run counterclockwise and holes clockwise. Map libraries still draw it, but a consumer that reads winding — Elasticsearch geo_shape, for one — takes it for a shape that crosses the dateline.","nestedGeometryCollection","A GeometryCollection contains another GeometryCollection. The specification recommends against nesting them because many tools do not handle it. Flatten the geometries into a single collection.","bboxMismatch","Some of the data falls outside the declared bbox. A hand-written bbox goes stale easily, so it is worth recalculating it from the data.","crsMember","This GeoJSON declares a \"crs\" member. RFC 7946 fixes every coordinate to WGS 84 and dropped that member, so its presence usually means the data was recorded in a different reference system — and it is drawn here as if it were WGS 84. A datum mismatch stays inside the valid coordinate range, so no other check catches it: data in the datum Japan used until 2002 lands about 464 m from where it belongs.","invalidTypeError","Valid JSON, but not GeoJSON. The \"type\" field must be one of: Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon, GeometryCollection, Feature, FeatureCollection.",{"_11":950,"_951":952,"_953":954,"_955":956,"_957":958,"_995":996,"_997":998,"_999":1000,"_208":335,"_210":1001,"_1005":1006,"_1007":1008,"_1009":1010,"_1011":1012,"_1020":1021,"_1022":1023,"_149":150,"_216":1031},"GeoJSON Guide","usageTitle","How to Use","usageDesc","Paste your GeoJSON into the text area and press View GeoJSON. Valid input is drawn on the map and reformatted with two-space indentation. The checks listed below are reported as errors and warnings. Click a shape to see the properties of that feature. If the document declares a bbox, it is drawn on the map as an orange dashed rectangle. Your input is never cleared, so you can fix it where it is.","typesTitle","The Nine GeoJSON Types","types",[959,963,967,971,975,979,983,987,991],{"_295":960,"_15":961,"_299":962},"Point","A single position.","{ \"type\": \"Point\", \"coordinates\": [139.7, 35.68] }",{"_295":964,"_15":965,"_299":966},"MultiPoint","An array of positions.","{\n \"type\": \"MultiPoint\",\n \"coordinates\": [[139.7, 35.68], [135.5, 34.7]]\n}",{"_295":968,"_15":969,"_299":970},"LineString","Two or more positions forming a line.","{\n \"type\": \"LineString\",\n \"coordinates\": [[139.7, 35.68], [135.5, 34.7]]\n}",{"_295":972,"_15":973,"_299":974},"MultiLineString","An array of LineStrings.","{\n \"type\": \"MultiLineString\",\n \"coordinates\": [\n [[139.70, 35.69], [139.77, 35.71]],\n [[139.70, 35.66], [139.77, 35.65]]\n ]\n}",{"_295":976,"_15":977,"_299":978},"Polygon","One or more closed rings. The first ring is the outer boundary; any others are holes.","{\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [139.7, 35.6], [139.8, 35.6],\n [139.8, 35.7], [139.7, 35.7],\n [139.7, 35.6]\n ]\n ]\n}",{"_295":980,"_15":981,"_299":982},"MultiPolygon","An array of Polygons.","{\n \"type\": \"MultiPolygon\",\n \"coordinates\": [\n [\n [\n [139.7, 35.6], [139.8, 35.6],\n [139.8, 35.7], [139.7, 35.7],\n [139.7, 35.6]\n ]\n ],\n [\n [\n [139.82, 35.6], [139.92, 35.6],\n [139.92, 35.7], [139.82, 35.7],\n [139.82, 35.6]\n ]\n ]\n ]\n}",{"_295":984,"_15":985,"_299":986},"GeometryCollection","A collection of geometries of mixed types.","{\n \"type\": \"GeometryCollection\",\n \"geometries\": [\n { \"type\": \"Point\", \"coordinates\": [139.70, 35.66] },\n {\n \"type\": \"LineString\",\n \"coordinates\": [\n [139.74, 35.68], [139.77, 35.71]\n ]\n }\n ]\n}",{"_295":988,"_15":989,"_299":990},"Feature","A geometry paired with a \"properties\" object. Properties carry information about the shape — a name, a population count, a category — rather than its geometry. Click a feature on the map to see them.","{\n \"type\": \"Feature\",\n \"geometry\": {\n \"type\": \"Point\",\n \"coordinates\": [139.7, 35.68]\n },\n \"properties\": { \"name\": \"Tokyo\" }\n}",{"_295":992,"_15":993,"_299":994},"FeatureCollection","An array of Features. To put more than one shape in a single document, list them here. This is the most common top-level type for real data.","{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"geometry\": {\n \"type\": \"Point\",\n \"coordinates\": [139.7, 35.68]\n },\n \"properties\": { \"name\": \"Tokyo\" }\n },\n {\n \"type\": \"Feature\",\n \"geometry\": {\n \"type\": \"Point\",\n \"coordinates\": [135.5, 34.7]\n },\n \"properties\": { \"name\": \"Osaka\" }\n }\n ]\n}","bboxTitle","About the bbox (bounding box)","bboxDesc","A bbox is the rectangle enclosing the whole document. It lets you see what extent the data covers without reading every coordinate. Editing the geometry puts it out of date, so generating it from the data is safer than typing it by hand. Write it as four numbers in the order west, south, east, north, or six for three dimensions with the minimum and maximum elevation. It is optional, and it can sit on a FeatureCollection, a Feature or a geometry. This page draws a declared bbox on the map as an orange dashed rectangle.","bboxExample","{\n \"type\": \"Polygon\",\n \"bbox\": [139.7, 35.6, 139.8, 35.7],\n \"coordinates\": [\n [\n [139.7, 35.6], [139.8, 35.6],\n [139.8, 35.7], [139.7, 35.6]\n ]\n ]\n}",[1002,1003,1004],"Most syntax errors come from a trailing comma, single quotes instead of double quotes, or unquoted keys. The error message reports the character position, so start reading there.","If a shape lands somewhere unexpected, suspect the coordinate order first. GeoJSON wants [longitude, latitude], but most map apps display \"latitude, longitude\", so copying from one to the other swaps them. A swap is caught as an error wherever the longitude exceeds 90, but between 90°W and 90°E both values stay in range and it passes unnoticed.","Data in a projected coordinate system — UTM, State Plane, Japan Plane Rectangular CS — must be reprojected to WGS84 before it will land in the right place.","validationTitle","What gets checked","validationDesc","Every time you press View GeoJSON, the document is checked against RFC 7946. Anything that makes the data impossible to draw is reported as an error; anything that still draws but should be fixed is reported as a warning. Nothing is uploaded — validation runs entirely in your browser.","validationErrorTitle","Errors","validationErrors",[1013,1014,1015,1016,1017,1018,1019],"The text does not parse as JSON.","A \"type\" is not valid for its position: the top level has to be one of the nine GeoJSON types, and a nested geometry one of the seven that are neither Feature nor FeatureCollection.","A single position is not an array of at least two finite numbers: an empty array where a position belongs, one number instead of two, or numbers written as strings.","A coordinate falls outside longitude ±180 or latitude ±90. Positions written as [latitude, longitude] show up here.","The nesting of \"coordinates\" does not match the geometry type, or it differs between branches.","A required member is missing.","A ring or a line has too few positions. A polygon ring needs four or more, a line two or more.","validationWarningTitle","Warnings","validationWarnings",[1024,1025,1026,1027,1028,1029,1030],"A ring is not closed: its first and last positions differ.","A ring breaks the right-hand rule. Outer rings should run counterclockwise and holes clockwise.","The third element of a position is not a number. It is the altitude, and it is optional, but it has to be numeric if it is there.","Something is wrong with the bbox: it cannot be read, its south is above its north, or the data falls outside it.","Something is wrong with the attributes: a Feature has no \"properties\", an \"id\" is neither a string nor a number, or the same property is a number in one feature and a string in another.","A GeometryCollection contains another GeometryCollection. The specification recommends against nesting them.","The document declares a \"crs\" member. RFC 7946 removed it and fixes all coordinates to WGS84, so its presence suggests the data may be in another reference system.",[1032,1035,1038,1041],{"_219":1033,"_221":1034},"Is the GeoJSON I paste sent to a server?","No. Parsing, validation and rendering all happen in your browser. Nothing is sent to a server, so you can paste data you are not allowed to share.",{"_219":1036,"_221":1037},"Why do I get \"Valid JSON, but not GeoJSON\"?","Your input parsed correctly as JSON, but its \"type\" field is missing or is not one of the nine GeoJSON types. A plain object such as {\"a\":1} is valid JSON and still not GeoJSON.",{"_219":1039,"_221":1040},"What exactly does it validate?","Errors, which stop anything being drawn: text that does not parse as JSON, a type that is not valid in the position it appears, positions that are not pairs of finite numbers or fall outside longitude ±180 and latitude ±90, a \"coordinates\" nesting that does not match the geometry type, missing required members, and rings or lines with too few positions. Warnings, which still draw: unclosed rings, rings that break the right-hand rule, and a bbox that cannot be read or does not contain the data. Coordinate precision is not checked. The \"What gets checked\" section lists them one by one.",{"_219":1042,"_221":1043},"Which comes first in GeoJSON, longitude or latitude?","Longitude comes first. RFC 7946 requires the first two elements to be longitude and latitude, in that order, and a bbox follows the same axis order: west, south, east, north. Many maps, Google Maps among them, show coordinates as \"latitude, longitude\", which makes it easy to get backwards, but GeoJSON always puts longitude first. Values written the other way usually land outside the valid range and are reported as an error.",[1045,1048,1051,1054],{"_11":1046,"_233":1047},"RFC 7946","The specification that defines GeoJSON. It fixes the coordinate reference system to WGS84 and the coordinate order to longitude then latitude, and defines exactly nine types. Documents written against the older 2008 GeoJSON 1.0 spec may use other coordinate systems.",{"_11":1049,"_233":1050},"CRS (coordinate reference system)","The agreement that decides what place a pair of numbers refers to. The same [139.7, 35.68] points somewhere different depending on which CRS you read it in. The 2008 version of GeoJSON had a \"crs\" member for declaring one; RFC 7946 dropped it and settled on WGS84 for everything, so a document that still carries \"crs\" predates the spec and may not be in WGS84 at all.",{"_11":1052,"_233":1053},"WGS84","The datum RFC 7946 fixes every coordinate to — the one GPS reports and web maps assume. A datum says where the coordinate system is anchored relative to the earth, so the same longitude and latitude means a different place under a different datum. Nothing in the numbers gives this away: a legacy datum stays comfortably inside ±180 and ±90 and lands a few hundred metres off.",{"_11":1055,"_233":1056},"The right-hand rule","The direction a polygon ring is wound. RFC 7946 asks for outer rings counterclockwise and holes clockwise. MapLibre and Leaflet draw a ring wound either way, so nothing looks different on the map. The consumers that read winding are the ones that store and search the data: Elasticsearch geo_shape takes a reversed polygon for one that crosses the dateline.","geocode",{"_11":1059,"_15":1060,"_31":1061,"_1062":1063,"_1064":1065,"_1066":1067,"_1068":1069,"_1070":1071,"_1072":1073,"_1074":1075,"_33":1085,"_55":1092,"_229":1141},"Geocode Viewer - Quadkey, Geohash & Plus Code","Online tool to convert latitude/longitude to Plus Codes, Quadkey, Geohash, and Grid Square Code. Visualize geocode grids on an interactive map.","Enter latitude and longitude to convert to various geocode formats and visualize grids on the map. Supports Plus Codes, Quadkey, Geohash, and Japan Grid Square codes. Useful for GIS development and location verification.","openlocationcode","Open Location Code","quadkey","Quadkey","geohash","Geohash","jisgrid","Grid Square Code","jisgridNote","This tool outputs World Grid Square codes, a global extension of the Japanese Grid Square Code (JIS X 0410). Remove the leading two digits to get the Japanese code.","codeError","The code could not be read.","jisgridLevels",[1076,1077,1078,1079,1080,1081,1082,1083,1084],"1st level (80km)","2nd level (10km)","3rd level (1km)","4th level (500m)","5th level (250m)","6th level (125m)","7th level (25m)","8th level (12.5m)","9th level (5m)",{"_1086":1087,"_1088":1089,"_1090":1091},"radio","Geocode type","lnglat","Longitude and latitude","level","Precision",{"_11":1093,"_1094":1095,"_1096":1097,"_1098":1099,"_1104":1105,"_204":1122,"_206":1123,"_325":1124,"_329":1125,"_149":150,"_216":1131},"Understanding Geocodes","comparisonTitle","Geocode Format Comparison","comparisonDesc","Several geocode formats exist, each with different characteristics regarding precision, coverage, and intended use cases.","comparisonHeaders",{"_177":277,"_1100":1091,"_1101":1102,"_181":1103},"precision","developer","Developer","Primary Use Case","comparison",[1106,1110,1114,1118],{"_177":1063,"_1100":1107,"_1101":1108,"_181":1109},"~14m × 14m (10-digit)","Google","Sharing locations without street addresses",{"_177":1065,"_1100":1111,"_1101":1112,"_181":1113},"Tile-level dependent","Microsoft","Bing Maps tile indexing and caching",{"_177":1067,"_1100":1115,"_1101":1116,"_181":1117},"~1.2km to ~2cm","Gustavo Niemeyer","Proximity search and database indexing",{"_177":1069,"_1100":1119,"_1101":1120,"_181":1121},"~1km to ~125m","JIS (Japan)","Japanese statistical and administrative data","How Geocodes Work","Geocodes encode latitude and longitude into compact strings by recursively dividing the Earth's surface into smaller grids. Each character in the resulting code narrows down the area, providing progressively finer precision. This approach enables efficient spatial indexing, fast proximity queries, and easy sharing of location information without requiring full coordinate pairs.","Use Cases",[1126,1127,1128,1129,1130],"Sharing precise locations in areas without formal street addresses","Efficient proximity searches in geospatial databases","Delivery and logistics location pinpointing","Map tile management and caching in web mapping services","Statistical analysis using standardized geographic grid units",[1132,1135,1138],{"_219":1133,"_221":1134},"What is a Plus Code?","Plus Code is Google's consumer-facing name for Open Location Code. It encodes any location into a short alphanumeric string (e.g., \"8Q7XMQH2+39\"). The \"+\" separates the area code from the local code. Plus Codes are useful for identifying locations in areas without formal addresses.",{"_219":1136,"_221":1137},"Which format provides the highest precision?","Geohash offers the most flexible precision — adding more characters increases accuracy from ~1.2km down to a few centimeters. Open Location Code provides ~14m precision at 10 digits. The best choice depends on your use case rather than raw precision alone.",{"_219":1139,"_221":1140},"Can Grid Square Code be used outside Japan?","Yes. The World Grid Square system extends JIS X 0410 (Grid Square Code) globally by dividing the world into 8 regions. The encoding method is identical, and the Japanese grid square code can be derived by removing the first two digits of the world grid square code.",[1142,1145,1147,1149],{"_11":1143,"_233":1144},"Open Location Code (Plus Codes)","The Open Location Code is a geocode based in a system of regular grids for identifying an area anywhere on the Earth. It was developed at Google's Zürich engineering office, and released late October 2014. Location codes created by the Open Location Code system are referred to as \"plus codes\".",{"_11":1065,"_233":1146},"Quadkey (Quadtree Key) is a geolocation hashing algorithm developed by Microsoft that divides regions based on latitude and longitude into grids of approximately the same size. Each quadkey has a single-digit code, zero to three. By zooming into the next level, each of the four original quadkeys splits into four, and we add another digit to the code.",{"_11":1067,"_233":1148},"Geohash is a method of encoding geographic location into a short string of characters. The encoded string represents a grid-based approximation of the location, allowing for fast and efficient indexing and retrieval of geographic data.",{"_11":1069,"_233":1150},"The Japanese grid square code (JIS X 0410) divides the country into nested cells based on latitude and longitude. The 1st level covers about 80km, the 2nd about 10km and the 3rd about 1km, which is the standard grid square used for Grid Square Statistics. Finer levels subdivide the 3rd level into cells of about 500m, 250m and 125m. The World Grid Square code that this tool outputs extends the same scheme to every location on Earth; removing the leading two digits yields exactly the Japanese grid square code.","wktGeojson",{"_11":1153,"_15":1154,"_31":1155,"_33":1156,"_156":1159,"_55":1164,"_229":1225},"WKT to GeoJSON Converter","Online WKT playground to convert WKT to GeoJSON (and back) and view on an interactive map. Supports PostGIS, SQL Server, and other GIS data.","Enter WKT or GeoJSON to convert between formats and view the result on an interactive map. Supports FeatureCollection to GEOMETRYCOLLECTION conversion. Useful for inspecting geospatial data from PostGIS, SQL Server, and similar systems.",{"_1157":1158,"_888":889},"wkt","WKT(Well-known text)",{"_1160":1161,"_1162":1163},"wktToJson","WKT to JSON","jsonToWkt","JSON to WKT",{"_11":1165,"_1166":1167,"_1168":1169,"_1170":1171,"_1174":1175,"_658":1195,"_660":1196,"_626":1197,"_208":335,"_210":1210,"_149":150,"_216":1215},"WKT & GeoJSON Guide","formatsTitle","Format Comparison","formatsDesc","WKT and GeoJSON are the two most common formats for representing geospatial data. Understanding their differences helps you choose the right format for your workflow.","formatHeaders",{"_1172":988,"_1157":1173,"_888":889},"feature","WKT","formats",[1176,1180,1184,1188,1192],{"_1172":1177,"_1157":1178,"_888":1179},"Format type","Plain text","JSON",{"_1172":1181,"_1157":1182,"_888":1183},"Primary use","Databases (PostGIS, SQL Server)","Web APIs & frontends",{"_1172":1185,"_1157":1186,"_888":1187},"Geometry types","POINT, LINESTRING, POLYGON, ...","Point, LineString, Polygon, ...",{"_1172":1189,"_1157":1190,"_888":1191},"Attribute data","Not supported","Stored in \"properties\"",{"_1172":1193,"_1157":1194,"_888":1046},"Standard","OGC / ISO 19162","WKT Examples","Here are common WKT geometry types you can paste into the converter above.",[1198,1201,1204,1207],{"_11":960,"_1157":1199,"_632":1200},"POINT(139.7671 35.6812)","A single coordinate point (Tokyo Station)",{"_11":968,"_1157":1202,"_632":1203},"LINESTRING(139.7671 35.6812, 139.6917 35.6895, 139.7454 35.6586)","A line connecting two or more points",{"_11":976,"_1157":1205,"_632":1206},"POLYGON((139.74 35.67, 139.78 35.67, 139.78 35.70, 139.74 35.70, 139.74 35.67))","A closed area (first and last coordinates must match)",{"_11":964,"_1157":1208,"_632":1209},"MULTIPOINT((139.7671 35.6812), (135.5023 34.6937))","Multiple separate points (Tokyo and Osaka)",[1211,1212,1213,1214],"Polygon coordinates must form a closed ring — the first and last points must be identical.","GeoJSON coordinates use [longitude, latitude] order, same as WKT.","In PostGIS, use ST_AsText() for WKT and ST_AsGeoJSON() for GeoJSON conversion.","Use FeatureCollection to group multiple geometries with their properties into a single GeoJSON document.",[1216,1219,1222],{"_219":1217,"_221":1218},"Should I use WKT or GeoJSON?","Use WKT for database storage and SQL queries (PostGIS, SQL Server). Use GeoJSON for web APIs, frontend map rendering, and data exchange between web services. Many tools support both, so the choice depends on your primary workflow.",{"_219":1220,"_221":1221},"What is the coordinate order?","Both WKT and GeoJSON use longitude first, then latitude (e.g., POINT(139.7 35.6) or [139.7, 35.6]). This differs from Google Maps and many GPS devices which display latitude first.",{"_219":1223,"_221":1224},"Can 3D coordinates be handled?","Yes. WKT supports POINT Z(139.7 35.6 100) for 3D coordinates. GeoJSON includes the altitude as the third element in the coordinates array: [139.7, 35.6, 100]. Note that altitude support varies across tools.",[1226,1229,1231,1234,1237],{"_11":1227,"_233":1228},"WKT (Well-Known Text)","WKT stands for Well-Known Text, which is a text representation of spatial data used in Geographic Information Systems (GIS). WKT is a standard format for describing geometric objects like points, lines, polygons, and multi-polygons in a way that is both human-readable and machine-readable. WKT is often used to exchange spatial data between different GIS systems or to store geometry information in databases.",{"_11":889,"_233":1230},"GeoJSON (Geographic JavaScript Object Notation) is a lightweight data interchange format for representing geographic spatial data. Based on the JSON format, GeoJSON is well-suited for expressing geographical shapes on a map. It combines the human-readable and machine-parseable features of JSON and is defined by RFC 7946.",{"_11":1232,"_233":1233},"PostGIS","PostGIS is an open-source spatial database extension for PostgreSQL. It adds support for geographic objects, allowing location queries to be run in SQL. PostGIS supports both WKT and GeoJSON formats and is one of the most widely used GIS databases.",{"_11":1235,"_233":1236},"OGC (Open Geospatial Consortium)","The Open Geospatial Consortium is an international organization that develops open standards for geospatial data. WKT, WKB, and many other spatial data formats and protocols are defined as OGC standards.",{"_11":992,"_233":1238},"A FeatureCollection is a GeoJSON object type that contains an array of Feature objects. Each Feature has a geometry (Point, Polygon, etc.) and a properties object for attribute data. FeatureCollections are the standard way to represent multiple geographic features in a single GeoJSON document.","shpGeojson",{"_11":1241,"_15":1242,"_31":1243,"_33":1244,"_156":1250,"_1254":1255,"_1256":1257,"_1260":1261,"_55":1262,"_229":1325},"Shapefile Viewer & GeoJSON Converter","View a Shapefile (.shp) on a map in your browser, free and with no install. Converts to GeoJSON (WGS84). Handles Tokyo Datum and JGD2000/2011.","Draws a shapefile on a map and converts it to GeoJSON (WGS84). When the ZIP has no .prj, it asks which datum to read the coordinates in before drawing and converting them. Everything runs in your browser.",{"_1245":1246,"_888":1247,"_1248":1249},"shp","Shapefile(zip file format)","List of converted GeoJSON file[s]","datum","Datum of the source data",{"_1251":157,"_1252":1253},"convert","clear","Clear","convertError","The file could not be converted. Check that the ZIP contains .shp, .shx and .dbf files sharing the same base name.","datumOptions",[1258,1259],"Modern global datum (WGS84 / JGD2000 / JGD2011)","Tokyo Datum (legacy Japanese datum, EPSG:4301)","noPrjNote","This ZIP contains no .prj file, so the coordinate system is unknown. Choose the datum the data was recorded in — the wrong choice shifts every feature by several hundred meters.",{"_11":1263,"_1264":1265,"_1266":1267,"_1268":1269,"_1274":1275,"_1292":1293,"_1294":1295,"_208":335,"_210":1296,"_1301":1302,"_1303":1304,"_1305":1306,"_1307":1308,"_149":150,"_216":1309},"Shapefile & GeoJSON Guide","componentsTitle","Shapefile Components","componentsDesc","A Shapefile is not a single file but a collection of files with the same base name and different extensions. Understanding these components helps ensure successful conversion.","componentHeaders",{"_1270":1271,"_1272":1273,"_15":74},"extension","Extension","required","Required","components",[1276,1279,1282,1285,1289],{"_1270":1277,"_1272":1273,"_15":1278},".shp","Geometry data (points, lines, polygons)",{"_1270":1280,"_1272":1273,"_15":1281},".shx","Spatial index for the geometry",{"_1270":1283,"_1272":1273,"_15":1284},".dbf","Attribute data (dBASE format)",{"_1270":1286,"_1272":1287,"_15":1288},".prj","Optional","Coordinate system. Without one, you pick the datum",{"_1270":1290,"_1272":1287,"_15":1291},".cpg","Character encoding. Without one, it is read from the .dbf","conversionTitle","About the Conversion","conversionDesc","The ZIP is read and converted to GeoJSON (WGS84). Attribute data from the .dbf is preserved in the \"properties\" member, and when the ZIP has no .cpg the encoding is taken from the .dbf header. Coordinates are reprojected from the .prj when one is present. Without a .prj a datum selector appears: coordinates in both datums look like ordinary longitude and latitude, so nothing in the file reveals which one was used. Japanese public data is sometimes published without a .prj in the legacy Tokyo Datum, and the wrong choice shifts every feature by several hundred meters.",[1297,1298,1299,1300],"The ZIP needs .shp, .shx and .dbf. If any of the three is missing, the file cannot be read.","A .prj is used automatically when present. Without one, pick the datum and the coordinates are converted from it to WGS84.","A ZIP with no .cpg still reads correctly: the encoding is taken from the .dbf header. Shift_JIS, common in Japanese shapefiles, comes through as it should.","A ZIP holding several layers gives you one GeoJSON download per layer.","datumTitle","Tokyo Datum and JGD — why your Shapefile is 464 m off","datumDesc","Japanese public data is sometimes published without a .prj file, recorded in the legacy Tokyo Datum (EPSG:4301) rather than a modern global datum. Coordinates in both look like ordinary longitude and latitude, so nothing in the file reveals which one was used — yet the same coordinates land about 464 m apart in central Tokyo. When a ZIP has no .prj file this tool shows a datum selector: choose a modern global datum (WGS84 / JGD2000 / JGD2011) to use the coordinates as they are, or the Tokyo Datum to reproject them to WGS84. A filename ending in -tky is a good hint that the data is in the legacy datum.","windingTitle","Ring orientation — Shapefile and GeoJSON disagree","windingDesc","A shapefile winds outer rings clockwise and holes counterclockwise. RFC 7946 (GeoJSON) asks for the opposite: outer rings counterclockwise, holes clockwise. Convert without adjusting and every polygon breaks the spec. MapLibre and Leaflet draw rings either way, so nothing looks wrong on the map. It surfaces once the data goes somewhere else: Elasticsearch geo_shape, for one, takes a reversed polygon for a shape that crosses the dateline and splits it there. This page rewinds rings to match RFC 7946. Note that d3-geo uses the same convention as a shapefile — clockwise outer rings — so RFC 7946 data renders inside out there. Rewind it again before handing it to d3-geo.",[1310,1313,1316,1319,1322],{"_219":1311,"_221":1312},"Which files should I include in the ZIP?","You need .shp, .shx and .dbf, all sharing the same base name. A .prj (coordinate system) and a .cpg (character encoding) are not required: without a .prj you pick the datum, and without a .cpg the encoding is read from the .dbf header.",{"_219":1314,"_221":1315},"Is the coordinate system converted automatically?","Yes, if a .prj file is included in the ZIP, coordinates are automatically reprojected to WGS84 (EPSG:4326), the standard for GeoJSON. Without a .prj file the datum cannot be detected, so a selector appears. Choosing a modern global datum (WGS84 / JGD2000 / JGD2011) uses the coordinates as they are; choosing the Tokyo Datum reprojects them to WGS84. The two are indistinguishable by value yet several hundred meters apart — about 464 m in central Tokyo.",{"_219":1317,"_221":1318},"How large a Shapefile can be converted?","A 1.7 MB archive of Japanese public data holding 38 layers and 47,352 features converts and draws without the page stalling. Since all processing happens in the browser, the practical limit depends on your device's memory, and extremely large datasets may fail to open.",{"_219":1320,"_221":1321},"How do I open a SHP file?","A Shapefile cannot be inspected on its own — it normally needs GIS software. On this page you select a ZIP containing the .shp, .shx and .dbf files, press Convert, and the data is drawn on the map. No installation, no login, free to use. Files are processed inside your browser and never sent to a server.",{"_219":1323,"_221":1324},"Can I view a Shapefile without installing QGIS?","Yes. If you want to check what is inside a file, or see the area a dataset someone sent you covers, this page is enough. You will still need QGIS or similar GIS software to edit attributes or run spatial analysis.",[1326,1329,1331,1334,1337,1340],{"_11":1327,"_233":1328},"Shapefile","A shapefile is a widely used geospatial vector data format developed by Esri. A Shapefile consists of multiple files (.shp, .shx, .dbf, .prj, etc.) that together represent geometry, spatial index, attribute data, and coordinate system information. It is the de facto standard for exchanging vector GIS data.",{"_11":889,"_233":1330},"GeoJSON (Geographic JavaScript Object Notation) is a lightweight data interchange format for representing geographic spatial data. Based on the JSON format, it supports Point, LineString, Polygon, and collection types. Defined by RFC 7946, it is widely used in web mapping applications.",{"_11":1332,"_233":1333},"WGS84 (EPSG:4326)","WGS84 (World Geodetic System 1984) is the standard coordinate reference system used by GPS. It defines latitude and longitude on an ellipsoidal model of the Earth. EPSG:4326 is the identifier code for WGS84. GeoJSON requires all coordinates to be in WGS84.",{"_11":1335,"_233":1336},"Tokyo Datum (EPSG:4301)","The datum used in Japan until 2002, based on the Bessel ellipsoid. The same place has different longitude and latitude values from those in a modern global datum, and the gap on the ground is several hundred meters — about 464 m in central Tokyo. Current data uses JGD2011, but older shapefiles still carry the legacy datum. Because its values span the same range, it cannot be told apart automatically when a .prj file is missing.",{"_11":1338,"_233":1339},"EPSG Code","EPSG codes are numeric identifiers for coordinate reference systems, maintained by the International Association of Oil & Gas Producers. Common examples include EPSG:4326 (WGS84), EPSG:3857 (Web Mercator), and EPSG:2451 (JGD2000 / Japan Plane Rectangular CS IX). The .prj file in a Shapefile defines which coordinate system is used.",{"_11":1341,"_233":1342},"dBASE (.dbf)","dBASE is a legacy database file format used by Shapefiles to store attribute data. The .dbf file contains tabular data associated with each geometric feature. While the format is old, it remains essential for Shapefile compatibility and is read by all GIS software.","web",{"_11":1345,"_15":1346,"_1347":1348},"Web Tools","Online web tools including OGP checker for meta tags and Twitter Card validation.","seo",{"_11":1349,"_15":1350,"_31":1351,"_33":1352,"_156":1353,"_35":36,"_1354":1355,"_229":1356,"_149":150,"_216":1369},"OGP Checker - X (Twitter) Card & Meta Tags","Enter a URL to check OGP tags, meta tags, and Twitter Cards at once. Preview how your page appears when shared on Facebook and X (Twitter) with realistic card mockups.","Enter a URL and click Check to inspect OGP tags, meta tags, and Twitter Card settings. See realistic previews of how your page looks when shared on Facebook, X (Twitter), and Threads.","Page URL to check:","Check","previewTitle","SNS Share Preview",[1357,1360,1363,1366],{"_11":1358,"_233":1359},"What is OGP?","OGP (Open Graph Protocol) is a metadata standard that controls how your content appears when shared on social networks like Facebook. By setting og:title, og:description, and og:image, you can customize the link preview display.",{"_11":1361,"_233":1362},"What are Twitter Cards?","Twitter Cards control how link previews appear when shared on X (Twitter). You can specify card types (summary, summary_large_image, etc.) using twitter:card. If OGP tags are set, they serve as fallbacks when Twitter-specific tags are not present.",{"_11":1364,"_233":1365},"What is robots.txt?","robots.txt is a file that instructs search engine crawlers which pages on your site they can or cannot access. It is placed at the site root and uses User-agent with Disallow/Allow rules for control.",{"_11":1367,"_233":1368},"What is a Canonical Tag?","A canonical tag tells search engines which URL is the authoritative version when duplicate content exists. Specified as , it prevents SEO value from being diluted across multiple URLs.",[1370,1373],{"_219":1371,"_221":1372},"What is the recommended OGP image size?","The recommended OGP image size for both Facebook and X is 1200×630px (aspect ratio 1.91:1). File size should be under 5MB, and supported formats include JPG, PNG, GIF, and WebP.",{"_219":1374,"_221":1375},"OGP not updating?","Social networks cache OGP information, so updates may not reflect immediately. Use Facebook's Sharing Debugger or X's Card Validator to clear the cache. Also, ensure og:image URLs use absolute paths.","games",{"_11":1378,"_13":1379,"_15":1380,"_1381":1382,"_1389":1390,"_1397":1398,"_1437":1438,"_1450":1451,"_1524":1525,"_1546":1547,"_1731":1732,"_1739":1740},"Bit Games","Browser Mini Games","Quick, casual games for whenever you have a moment. All games work on both desktop and mobile browsers.","features",{"_1383":1384,"_1385":1386,"_1387":1388},"free","Runs in browser","noInstall","Desktop & mobile","mobile","Mobile friendly","categories",{"_1391":1392,"_1393":1394,"_1395":1396},"puzzle","Puzzle","arcade","Arcade","simulation","Simulation","minesweeper",{"_11":1399,"_15":1400,"_31":1401,"_1402":1403,"_1404":1405,"_1410":1411,"_1412":1413,"_1414":1415,"_1416":1417,"_1418":1419,"_1420":1421,"_39":40,"_41":42,"_1422":1423,"_1424":1425,"_1429":1430,"_1431":1432,"_1433":1434,"_1435":1436},"Minesweeper - Classic Puzzle Game","Play Minesweeper online. Clear a board and share it as a link — the whole board fits in the URL. Shows 3BV and 3BV/s. Works on mobile.","A classic puzzle game where you clear a minefield without detonating any mines. Three levels: Beginner, Intermediate, and Expert. Clear a board and you get 3BV and 3BV/s alongside your time, so you can see how fast you solve regardless of the board you were dealt. Results can be shared as a link: the board you won fits in the URL itself, so whoever opens it sees it exactly as it stood, down to which mines you flagged.","placeFlag","Place a flag","levels",[1406,1407,1408,1409],"Beginner","Intermediate","Expert","Beginner (classic)","cleared","Won","failed","Lost","time","Time","sharedResult","A shared result","shareHint","Clear the board and you can share it as a link — whoever opens it sees the board exactly as you left it.","shareExample","See a shared link","rulesTitle","Rules","rules",[1426,1427,1428],"The board is divided into cells, with mines randomly distributed. To win, you need to open all the cells. The number on a cell shows the number of mines adjacent to it. Using this information, you can determine cells that are safe, and cells that contain mines. Cells suspected of being mines can be marked with a flag check the 'Place a flag'.","To start a new game, you can click on the Reset button at the top of the board. The remaining number of mines is displayed in the left corner, and the game timer is displayed in the right corner.","Clear the board and your time appears below it, along with 3BV — a number for how hard the board was. The share button copies a link that shows your result to whoever opens it. 3BV is explained in the next section.","bbbvTitle","3BV — how hard the board is","bbbvDesc","3BV, short for Bechtel's Board Benchmark Value, is the smallest number of left clicks that would clear the board. Opening one empty cell cascades through every empty cell it touches, so a whole connected area counts as a single click; a number that borders no empty area has to be clicked on its own. The value comes from the layout alone — flags and chords do not change it.","bbbvWhy","Time on its own does not say much, because an easy board clears faster than a hard one. Dividing 3BV by your time gives 3BV/s, which is how fast you solve regardless of the board you were dealt. It is the figure competitive players compare.","bbbvTypical","Over 2000 random boards per level, the median 3BV was 15 on Beginner, 65 on Intermediate and 173 on Expert. Ranking sites discard boards below 5, 30 and 100 respectively. A low 3BV only means fewer clicks. When mines sit close together a single click opens a large empty area, which lowers the 3BV but also leaves fewer numbered cells to work out where the mines are.","invaders",{"_11":1439,"_15":1440,"_31":1441,"_1442":1443,"_1422":1423,"_1424":1444},"Space Invaders - Retro Arcade Game","Play a classic Space Invaders-style arcade game. Arrow keys to move, Space to shoot. Stage-based gameplay, works on desktop and mobile.","A classic arcade game inspired by Space Invaders. Destroy all the invaders before they reach you! Use arrow keys to move and Space to shoot. Features stage-based progression on desktop and mobile.","controls","Controls: Arrow keys to move, Space to shoot",[1445,1446,1447,1448,1449],"Destroy all invaders to clear the stage. Invaders move left and right, gradually descending.","Use the arrow keys to move your ship left and right. Press the Space key to fire bullets.","Barriers will protect you from enemy fire, but they gradually break down when hit.","If an invader reaches your position or you are hit by enemy fire, the game is over.","Click the screen to start the next level after clearing a stage.","automaton",{"_11":1452,"_15":1453,"_55":1454,"_229":1523},"Cellular Automaton Simulator - Game of Life, ECA","Run Conway's Game of Life and all 256 Elementary Cellular Automaton rules in your browser. Set custom initial states and observe complex pattern generation.",{"_11":1455,"_1456":1457,"_1458":1459,"_955":1460,"_1461":1462,"_1463":1464,"_957":1468,"_1485":1486,"_1487":1488,"_1489":1490,"_1491":1492,"_1493":1494,"_1495":1496,"_1497":1498,"_1499":1500,"_1501":1502,"_1503":1504,"_149":150,"_216":1510},"What Are Cellular Automata?","introTitle","Overview","introDesc","Cellular automata (CA) are discrete computational models consisting of a grid of cells, each in one of a finite number of states. At each time step, every cell updates its state simultaneously based on a fixed rule that considers the states of its neighboring cells. Despite their simplicity, cellular automata can produce remarkably complex behaviors — from stable patterns to chaotic dynamics — making them a powerful tool for studying emergence and self-organization.","Types of Cellular Automata","typesDesc","Cellular automata come in many forms depending on their dimensionality, neighborhood definition, and rule structure. This site offers simulators for Conway's Game of Life (2D) and all 256 Elementary Cellular Automaton rules (1D).","typeHeaders",{"_177":296,"_1465":1466,"_299":1467},"dimensions","Dimensions","Notable Example",[1469,1473,1477,1481],{"_177":1470,"_1465":1471,"_299":1472},"Elementary CA","1D","Wolfram's 256 rules (Rule 30, Rule 110)",{"_177":1474,"_1465":1475,"_299":1476},"Totalistic CA","1D / 2D","Rules based on sum of neighbor states",{"_177":1478,"_1465":1479,"_299":1480},"Life-like CA","2D","Conway's Game of Life (B3/S23)",{"_177":1482,"_1465":1483,"_299":1484},"Continuous CA","2D+","Lenia, SmoothLife","lifeTitle","Conway's Game of Life","lifeDesc","The Game of Life is a 2D cellular automaton created by mathematician John Horton Conway in 1970. It follows birth/survival rules (B3/S23): a dead cell with exactly 3 live neighbors is born, and a live cell with 2 or 3 live neighbors survives. From these simple rules emerge diverse patterns like gliders and pulsars, and the system has been proven Turing complete.","ecaTitle","Elementary Cellular Automaton (ECA)","ecaDesc","An elementary cellular automaton is the simplest type of CA, where each cell has two states (0/1) and its next state is determined by itself and its two neighbors (3 cells total). Since there are 8 possible combinations of 3 cells, exactly 256 rules (numbered 0–255) exist. They range from Rule 30, which produces chaotic patterns used in random number generation, to Rule 110, which is proven Turing complete.","rule110Title","What Is Rule 110?","rule110Desc","Rule 110 is an elementary cellular automaton rule where each cell's next state is determined by its current state and its two immediate neighbors (3 cells total). The output pattern reads as \"01101110\" in binary, or \"110\" in decimal — hence the name. When run, it produces a distinctive mix of regular triangular patterns and chaotic regions.","historyTitle","Brief History","historyDesc","Cellular automata were first studied by Stanislaw Ulam and John von Neumann in the 1940s at Los Alamos National Laboratory. Von Neumann was interested in self-replicating systems and designed a 2D CA capable of universal computation. In 1970, John Conway created the Game of Life, which became widely popular and demonstrated how complex behavior emerges from simple rules. In the 1980s, Stephen Wolfram systematically studied elementary cellular automata, classifying their behavior into four classes: Class 1 (uniform), Class 2 (periodic), Class 3 (chaotic/random), and Class 4 (complex/edge of chaos). He proposed that simple programs can generate complexity comparable to natural phenomena.","applicationsTitle","Applications","applications",[1505,1506,1507,1508,1509],"Modeling physical phenomena (crystal growth, fluid dynamics, diffusion)","Biological simulations (population dynamics, pattern formation)","Cryptography and random number generation (Rule 30)","Traffic flow simulation and urban planning","Theoretical computer science (computation universality, complexity theory)",[1511,1514,1517,1520],{"_219":1512,"_221":1513},"Are cellular automata Turing complete?","Some are. Rule 110 in elementary cellular automata and Conway's Game of Life have been proven to be Turing complete, meaning they can simulate any computation that a Turing machine can perform.",{"_219":1515,"_221":1516},"What is the difference between Game of Life and Elementary CA?","Game of Life operates on a 2D grid where each cell has 8 neighbors (Moore neighborhood) and uses birth/survival rules. Elementary CA operates on a 1D row where each cell has 2 neighbors, with 256 possible rule sets. Both are deterministic zero-player systems.",{"_219":1518,"_221":1519},"Who invented cellular automata?","The concept was developed by Stanislaw Ulam and John von Neumann in the 1940s. Von Neumann designed a self-replicating CA as a theoretical model for biological reproduction. The field gained popular attention with Conway's Game of Life (1970) and Wolfram's systematic studies (1980s).",{"_219":1521,"_221":1522},"Can I use these simulators on mobile?","Yes. Both the Game of Life and Elementary CA simulators run entirely in your browser and are responsive. Performance depends on your device, but modern smartphones handle them well.",[],"life",{"_11":1526,"_15":1527,"_31":1528,"_1422":1423,"_1424":1529,"_1535":1536,"_1537":1538,"_1544":1545},"Conway's Game of Life Simulator","Experience Conway's Game of Life (B3/S23) in your browser. Place Gliders, Pulsars, Glider Guns and more to observe the birth, survival, and death of cells. Powered by high-speed Bitboard algorithm.","A 2D cellular automaton devised by John Conway in 1970. Simple rules of birth, survival, and death give rise to surprisingly complex patterns like Gliders and Pulsars. Experience high-speed generation updates with the Bitboard algorithm.",[1530,1531,1532,1533,1534],"The universe of the Game of Life is an infinite, two-dimensional orthogonal grid of square cells, each of which is in one of two possible states, live or dead (or populated and unpopulated, respectively).","The rules are known as B3/S23:","1. Birth (B3): Any dead cell with exactly three live neighbours becomes a live cell.","2. Survival (S23): Any live cell with two or three live neighbours survives.","3. Death: All other live cells die in the next generation. Similarly, all other dead cells stay dead.","aboutTitle","What is Conway's Game of Life?","about",[1539,1540,1541,1542,1543],"The Game of Life is a cellular automaton devised by British mathematician John Horton Conway in 1970. On a two-dimensional grid, cells with two states — alive or dead — evolve through generations following four simple rules.","The only input from the player is the initial configuration; after that, the system evolves automatically, which is why it is called a \"zero-player game.\" A hallmark of the Game of Life is that remarkably complex patterns emerge from simple rules.","Patterns in the Game of Life fall into three main categories: still lifes (Block, Beehive, etc.), oscillators (Blinker, Pulsar, etc.), and spaceships (Glider, Lightweight Spaceship, etc.). The Glider, which travels across the grid indefinitely, is perhaps the most iconic pattern.","The Game of Life has been proven to be Turing complete, meaning it can theoretically simulate any computer program. This property makes it an important model in computation theory, complex systems science, and artificial life research.","This simulator uses a Bitboard algorithm. Each cell's state is represented as a single bit (0/1), and a 64-bit integer holds the state of 64 cells at once. By shifting bits to align neighbor information and using adder logic (AND, XOR) to count live neighbors in parallel, it evaluates the next generation for 64 cells in just a few bitwise operations — dramatically faster than checking cells one by one.","aboutMore","Learn more about the history and applications of cellular automata","eca",{"_11":1548,"_15":1549,"_31":1550,"_33":1551,"_1566":1567,"_1422":1423,"_1568":1569,"_1570":1571,"_1577":1578,"_1579":1580,"_1581":1582,"_1584":1585,"_1586":1587,"_1535":1593,"_1537":1594,"_1596":1597,"_1598":1599,"_1600":1601,"_1602":1603,"_1604":1605,"_1606":1607,"_1608":1609,"_1610":1611,"_1612":1613,"_1544":1545,"_1614":1615,"_1616":1617,"_1618":1619,"_1620":1621,"_1622":1623,"_1624":1625,"_1626":1627,"_1628":1629,"_1630":1631,"_1632":1633,"_1634":1635,"_1636":1637,"_1638":1639,"_1640":1641,"_1642":1643,"_1644":1645,"_1646":1647,"_1648":1649,"_1650":1651,"_1652":1653,"_1654":1655,"_1656":1657,"_1658":1659,"_1660":1661,"_1662":1663,"_1664":1665,"_1666":1667,"_1668":1669,"_1670":1671,"_1672":1673,"_1674":1675,"_1676":1677,"_1678":1679,"_1680":1681,"_1682":1683,"_1684":1685,"_1686":1687,"_1688":1689,"_1690":1691,"_1692":1693,"_1694":1695,"_1696":1697,"_1698":1699,"_1700":1701,"_1702":1703,"_1704":1705,"_1706":1707,"_1708":1709,"_1710":1711,"_1718":1719,"_1720":1721,"_1722":1723,"_1724":1725},"Elementary Cellular Automaton Simulator & Rule Table","Explore all 256 Elementary Cellular Automaton (ECA) rules with the simulator and complete output mapping table. Compare every rule's output for each 3-cell pattern (111 through 000). Simulate Rule 30, Rule 110, and any rule instantly in your browser.","Explore all 256 Elementary Cellular Automaton (ECA) rules with the simulator and complete output mapping table. Enter any rule number to watch its pattern evolve in real time, and compare every rule's output at a glance. Notable rules include Turing-complete Rule 110 and chaotic Rule 30. For a detailed explanation of how ECA works and Wolfram's four classes, see the sections below.",{"_1552":1553,"_1554":1555,"_1556":1557,"_1558":1559,"_1560":1561,"_1562":1563,"_1564":1565},"rule","Rule number(0-255)","initialState","Initial state","initialStateSingle","Single cell","initialStateRandom","Random","pattern","Rule table","currentCells","Current 3 cells","nextGeneration","Next generation","equivalenceMirrorTitle","Left-right symmetry","rulesIntro","An elementary cellular automaton works in the following steps:","rulesSteps",[1572,1573,1574,1575,1576],"Start with a row of cells as the initial state. Each cell holds a state of 0 (dead) or 1 (alive). The cells at each end wrap around to the opposite side, forming a ring (periodic boundary conditions)","For each cell, look at the 3-cell neighborhood: its left neighbor, itself, and its right neighbor","Look up the 3-cell combination in the rule table (a lookup table that defines the next value for each combination) to determine that cell's value in the next generation","Update all cells simultaneously to produce the next generation (compute the next value for every cell first, then replace them all at once)","Repeat steps 2–4 to advance through generations. In this simulator, each generation is drawn as one row from top to bottom","rulesExampleTitle","How rule numbers work","rulesExample","There are 2³ = 8 possible 3-cell combinations (111 through 000), and a rule is a lookup table that specifies the next-generation value (0 or 1) for each. For example, Rule 110:","rulesSteps2",[1583],"The 8 outputs lined up give 01101110₂, which converts to 110₁₀ in decimal — this becomes the rule number. There are 2⁸ = 256 possible rules in total","rulesVisualTitle","Step-by-step example","rulesVisual",[1588,1589,1590,1591,1592],"1. Prepare the initial state\n\n A row of cells, each holding 0 or 1.\n\n Gen 0: [0] [0] [1] [0] [0]","2. Look at each cell's neighborhood\n\n For each cell, look at left, center, and right as a set.\n The cells at each end wrap around to the opposite side, forming a ring (periodic boundary conditions).\n\n left center right\n ↓ ↓ ↓\n [0] [0] [1] [0] [0]","3. Look up the next state in the rule table\n\n Match the 3-cell combination against the rule table to get the next value.\n\n e.g. Rule 110:\n (0,1,0) → rule table lookup → 1","4. Update all cells simultaneously\n\n Apply the rule to every cell at once to produce the next generation.\n\n e.g. Rule 110:\n Gen 0: [0] [0] [1] [0] [0]\n ↓ all cells update at once\n Gen 1: [0] [1] [1] [0] [0]","5. Repeat\n\n Repeat 2→3→4 to advance through generations. Stacking them vertically creates a 2D pattern.","What is an Elementary Cellular Automaton?",[1595],"Elementary Cellular Automata (ECA) were systematically studied by Stephen Wolfram in the 1980s and represent the simplest form of cellular automaton. Despite having only 256 possible rules, their behavior is remarkably diverse. Wolfram classified this behavior into four classes.","aboutClass1Title","Class 1 — Uniform","aboutClass1","Regardless of initial conditions, all cells converge to the same state within a few generations. All information from the initial state is completely lost — the simplest possible behavior.","aboutClass2Title","Class 2 — Periodic","aboutClass2","Settles into stable patterns such as stripes or fixed points and repeats them indefinitely. Some influence from the initial conditions is preserved locally, but overall behavior remains predictably orderly.","aboutClass3Title","Class 3 — Chaotic","aboutClass3","Generates aperiodic, random-looking patterns indefinitely. Tiny differences in initial conditions lead to entirely different outcomes, making long-term prediction impossible. Yet because these patterns are generated by deterministic rules, they can be used as pseudorandom number generators.","aboutClass4Title","Class 4 — Complex","aboutClass4","Sits at the boundary between order (Classes 1–2) and chaos (Class 3). Information neither freezes as in Classes 1–2 nor disperses as in Class 3. In this delicate balance, \"gliders\" — structures that maintain their shape while moving — emerge spontaneously. Gliders can carry information, and their collisions produce new patterns. This ability to preserve, transmit, and transform information is what makes computation possible.","aboutOutro","Among the 256 rules, several stand out: Rule 30 is used for chaotic random number generation, Rule 110 has been proven Turing complete, Rule 90 generates the Sierpinski triangle, and Rule 184 models traffic flow. Below, we explore these and other notable rules by class.","class12Title","Notable Class 1 & 2 Rules — Orderly","class12Intro","In Class 1, rules like Rule 0 (all cells converge to 0) and Rule 255 (all cells converge to 1) cause every cell to reach the same state within a few generations. Class 2, on the other hand, contains many interesting rules — including Sierpinski-family rules that generate fractal patterns and rules that simulate traffic flow.","class3Title","Notable Class 3 Rules — Chaos","class4Title","Notable Class 4 Rules — Complexity","class4Intro","The \"gliders\" described above can be observed in action by running Class 4 rules in the simulator. In Rules 110 and 54, structures that maintain their shape emerge within the periodic background pattern, moving at different speeds. When gliders collide, they produce complex interactions — annihilation, merging, and splitting.","class4TuringTitle","Class 4 Supplement — Turing Completeness","sierpinskiTitle","Sierpinski Triangle","sierpinskiIntro","One of the most famous patterns in ECA is the Sierpinski triangle (Sierpinski gasket). Starting from a single ON cell, a self-similar fractal triangle emerges.","sierpinskiExactTitle","Exact Sierpinski triangle","sierpinskiExact","Rules 18, 90, and 146 produce symmetric Sierpinski triangles. Rule 60 produces a right-leaning triangle, and Rule 102 produces a left-leaning triangle (these two are mirror equivalents).","sierpinskiSingleTitle","Sierpinski from single cell only","sierpinskiSingle","Rules 26, 154, 210, and 218 produce a Sierpinski triangle from a single-cell initial condition, but exhibit different behavior with random initial conditions.","sierpinskiLikeTitle","Sierpinski-like fractals","sierpinskiLike","Rules 22, 122, 126, and 150 produce fractal patterns that resemble the Sierpinski triangle but are not strictly identical to it.","sierpinskiInvertedTitle","Color-Inverted Sierpinski","sierpinskiInverted","Rules 60, 90, and 102 — which generate Sierpinski patterns — are palindrome rules (explained below), and their equivalents Rules 195, 165, and 153 produce color-inverted Sierpinski patterns. Likewise, Rule 126 (Sierpinski-like) is a palindrome rule, and its equivalent Rule 129 produces an inverted Sierpinski-like fractal.","sierpinskiEquivalentTitle","Other Equivalent Sierpinski Rules","sierpinskiEquivalent","Rule 183 (reverse+flip of Rule 18) and Rule 182 (reverse+flip of Rule 146) also produce equivalent Sierpinski patterns.","chaosTitle","Chaos and Complexity","chaosIntro","Of the four classes described above, Class 3 (chaotic) and Class 4 (complex) are the most noteworthy.","chaosClass3Title","Class 3 — Chaos","chaosClass3","Produces aperiodic, random-looking patterns. Rule 30 is famously used in Mathematica's random number generator. Rules 45 and 106 also exhibit chaotic behavior.","chaosClass4Title","Class 4 — Complexity","chaosClass4","Sits at the boundary between orderly Classes 1–2 and chaotic Class 3. Neither fully regular nor fully random, these rules produce \"gliders\" — moving local structures that emerge naturally and interact through collisions. This is what makes them capable of computation, as explained below.","turingTitle","Turing Completeness","turingIntro","Turing completeness means the ability to perform any computation given the right initial conditions. Class 4 (complex) is neither too orderly nor too chaotic, which makes this possible. In orderly rules, information becomes fixed; in chaotic rules, information disperses and is lost. In Class 4, gliders can preserve and transmit information, enabling computation.","turingRule110Title","Rule 110","turingRule110","Proven Turing complete by Matthew Cook in 2004, demonstrating that this simple rule can simulate any computation.","turingRule54Title","Rule 54","turingRule54","Conjectured to be Turing complete, but not yet proven. Like Rule 110, it produces gliders. From a single-cell initial condition, it produces left-right symmetric output.","trafficTitle","Traffic Model","trafficIntro","Rule 184 is a particle-conserving rule used for traffic flow simulation. Treating black cells as cars and white cells as empty space, a car advances one cell if the space ahead is empty, and stops if blocked.","equivalenceTitle","What are Equivalent Rules?","equivalenceIntro","Among the 256 rules, there are \"equivalent rules\" that generate patterns with the same structure. Equivalent rules are related by the following three transformations:","equivalenceMirror","Swapping the left and right cells in each neighborhood pattern (swap) produces a left-right symmetric pattern. When a rule produces symmetric output from a single cell (e.g., Rules 26 and 82, Rules 30 and 86), the transformation looks identical, so use random initial conditions to see the difference.","equivalenceReverseFlipTitle","Black-white symmetry","equivalenceReverseFlip","Reversing the bit order and then flipping each bit (reverse+flip) produces a black-white symmetric pattern. This is different from a simple bit-flip (complement). When the initial condition is also color-inverted, the output becomes the color-inverted version of the original pattern. However, some pairs such as Rule 110 and Rule 137 produce color-inverted patterns even from the same single-cell initial condition.","equivalenceMirrorReverseFlipTitle","Left-right + Black-white symmetry","equivalenceMirrorReverseFlip","Combines the two transformations above. First swaps left and right cells in each neighborhood pattern, then reverses the bit order and flips each bit.","equivalenceNoteTitle","Special Case of Black-White Symmetry — When the Rule Is a Palindrome","equivalenceNote","When a rule's bit string is a palindrome (reads the same forwards and backwards), flipping the input bits alone causes the output bits to flip as well. Normally, black-white symmetry requires reverse+flip (reversing the order then flipping), but for palindrome rules the bit string is unchanged when reversed, so flip alone is sufficient. For example, Rule 90 (01011010) is a palindrome, so 255 - 90 = Rule 165 (10100101) is its equivalent.","equivalenceCautionTitle","Note","equivalenceCaution","The swap in left-right symmetry swaps the left and right cells of each neighborhood pattern (3 bits). For example, neighborhood pattern 110 (position 6) becomes 011 (position 3) when left and right are swapped, so bit positions 6 and 3 are exchanged in the rule's bit string (8 bits). Similarly, 100 (position 4) and 001 (position 1) are exchanged. Symmetric patterns (111, 101, 010, 000) remain unchanged. For example, Rule 110 (01101110): bit positions 6 and 3 are both 1 (unchanged), while bit position 4 (0) and position 1 (1) are swapped, giving 01111100 = Rule 124.","independentRulesTitle","The 88 Independent Rules","independentRulesIntro","Applying the three equivalence transformations above reduces the 256 ECA rules to 88 independent representatives. Every other rule is equivalent to one of these.","allRulesTitle","All 256 Rules — Output Mapping Table","allRulesCaption","Complete output mapping for all 256 ECA rules","independentRule","Independent rule","equivalenceTypeLabels",{"_1712":1713,"_1714":1715,"_1716":1717},"mirror","left-right symmetry","complement","black-white symmetry","mirrorComplement","left-right + black-white symmetry","palindromeLabel","palindrome","noteSeparator"," — ","equivalentRuleFormat","Equivalent to Rule {0} ({1})","allRulesHeaders",{"_1552":1726,"_1727":1728,"_1729":1730},"Rule","class","Class","notes","Notes","tetrimimus",{"_11":1733,"_15":1734,"_31":1735,"_1422":1423,"_1424":1736},"Tetrimimus - Tetris-style Falling Blocks","Play a falling-block puzzle game in your browser. Studies show that just 3 minutes of block-puzzle play can reduce stress.","A falling-block puzzle game. Rotate and move blocks to clear lines. Research suggests that short sessions of block-puzzle games can help reduce stress. Give your tired brain a 3-minute refresh.",[1737,1738],"A single-sided tetromino block piece, constructed by combining four squares, falls randomly from the upper part of the field, one type at a time.","When any 1 to 4 rows of the grid are completely filled with blocks, those rows disappear, and points are awarded based on the number of rows cleared. Clearing multiple rows simultaneously (up to 4 rows) results in higher points.","pacBoy",{"_11":1741,"_15":1742,"_31":1743,"_1422":1423,"_1424":1744},"Pac-Boy - 1D Pac-Man Style Dot-Eating Game","Play Pac-Boy, a 1D dot-eating game inspired by Pac-Man. A remake of ABA Games' PAKU PAKU.","A 1D dot-eating game similar to Pac-Man. A remake of ABA Games' PAKU PAKU. Eat dots while evading enemies.",[1745,1746,1747],"The player's goal is to eat as many dots as possible while evading the enemies.","After eating a large dot, the player can eat the enemies for a limited time.","Once all the dots have been eaten, new dots will appear.","en-home",{"_5":6,"_7":1750},{"_11":1751,"_15":1752,"_1753":1754,"_9":1755,"_1376":2048},"Tools for developers, games for a break.","LaTeX equation preview, JSON formatter, hash generator and more developer tools — plus Minesweeper, Tetris and other mini games. 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