The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 28 hours. Why not try and solve them ahead of time?
Set in all languages in chars. Achievements Cheevos Holes Languages Medals Miscellaneous All Holes 12 Days of Christmas 24 Game 99 Bottles of Beer Abundant Numbers Abundant Numbers (Long) Arabic to Roman Arithmetic Numbers Arrows Ascending Primes ASCII Table Billiards brainfuck Calendar Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz Continued Fractions CSS Colors Cubes Day of Week DFA Simulator Diamonds Divisors Emirp Numbers Emirp Numbers (Long) Emojify Evil Numbers Evil Numbers (Long) Factorial Factorisation Farey Sequence Fibonacci Fizz Buzz Foo Fizz Buzz Bar Forsyth–Edwards Notation Fractions Game of Life Gijswijt’s Sequence Happy Numbers Happy Numbers (Long) Hexdump Hilbert Curve Intersection Inventory Sequence ISBN Jacobi Symbol Kaprekar Numbers Kolakoski Constant Kolakoski Sequence Leap Years Levenshtein Distance Leyland Numbers ln 2 Look and Say Lucky Numbers Lucky Tickets Mahjong Mandelbrot Maze Medal Tally Minesweeper Morse Decoder Morse Encoder Multitap Input Musical Chords N Queens Niven Numbers Niven Numbers (Long) Number Spiral Odious Numbers Odious Numbers (Long) Ordinal Numbers PalindromemordnilaP Pangram Grep Partition Numbers Pascal’s Triangle Pernicious Numbers Pernicious Numbers (Long) Poker Polyominoes Prime Numbers Prime Numbers (Long) Proximity Grid QR Decoder Quine Recamán Repeating Decimals Reverse Polish Notation Reversi Rijndael S-box Rock-paper-scissors-Spock-lizard Roman to Arabic ROT13 Rule 110 Scrambled Sort Set Seven Segment SI Units Sierpiński Triangle Smith Numbers Spelling Numbers Star Wars GPT Star Wars Opening Crawl Sudoku Sudoku (Fill-in) Ten-pin Bowling Tic-tac-toe Time Distance Tongue-twisters Topological Sort Tower of Hanoi Transpose Sentence Trinomial Triangle United States Vampire Numbers Van Eck Sequence Zeckendorf Representation Zodiac Signs γ λ π τ φ √2 𝑒 Alphabetic Numbers Apéry’s Constant Binary Lambda Calculus Connect Four Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Rectangle Fill Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial All Languages ><> ALGOL 68 ArkScript Assembly AWK Bash BASIC Berry brainfuck C C# C++ Civet Clojure COBOL Coconut Common Lisp Crystal D Dart Elixir Erlang F# Factor Forth Fortran Gleam Go GolfScript Groovy Haskell Hexagony J Janet Java JavaScript jq Julia K Kotlin Lua Nim OCaml Pascal Perl PHP PowerShell Prolog Python R Raku Rockstar Ruby Rust Scheme sed SQL Swift Tcl TeX V VimL Wren Zig 05AB1E APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Lily Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Bytes Chars Scoring Bytes Chars Language All ><> ALGOL 68 ArkScript Assembly AWK Bash BASIC Berry brainfuck C C# C++ Civet Clojure COBOL Coconut Common Lisp Crystal D Dart Elixir Erlang F# Factor Forth Fortran Gleam Go GolfScript Groovy Haskell Hexagony J Janet Java JavaScript jq Julia K Kotlin Lua Nim OCaml Pascal Perl PHP PowerShell Prolog Python R Raku Rockstar Ruby Rust Scheme sed SQL Swift Tcl TeX V VimL Wren Zig Experimental Language 05AB1E APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Lily Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Hole All 12 Days of Christmas 24 Game 99 Bottles of Beer Abundant Numbers Abundant Numbers (Long) Arabic to Roman Arithmetic Numbers Arrows Ascending Primes ASCII Table Billiards brainfuck Calendar Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz Continued Fractions CSS Colors Cubes Day of Week DFA Simulator Diamonds Divisors Emirp Numbers Emirp Numbers (Long) Emojify Evil Numbers Evil Numbers (Long) Factorial Factorisation Farey Sequence Fibonacci Fizz Buzz Foo Fizz Buzz Bar Forsyth–Edwards Notation Fractions Game of Life Gijswijt’s Sequence Happy Numbers Happy Numbers (Long) Hexdump Hilbert Curve Intersection Inventory Sequence ISBN Jacobi Symbol Kaprekar Numbers Kolakoski Constant Kolakoski Sequence Leap Years Levenshtein Distance Leyland Numbers ln 2 Look and Say Lucky Numbers Lucky Tickets Mahjong Mandelbrot Maze Medal Tally Minesweeper Morse Decoder Morse Encoder Multitap Input Musical Chords N Queens Niven Numbers Niven Numbers (Long) Number Spiral Odious Numbers Odious Numbers (Long) Ordinal Numbers PalindromemordnilaP Pangram Grep Partition Numbers Pascal’s Triangle Pernicious Numbers Pernicious Numbers (Long) Poker Polyominoes Prime Numbers Prime Numbers (Long) Proximity Grid QR Decoder Quine Recamán Repeating Decimals Reverse Polish Notation Reversi Rijndael S-box Rock-paper-scissors-Spock-lizard Roman to Arabic ROT13 Rule 110 Scrambled Sort Set Seven Segment SI Units Sierpiński Triangle Smith Numbers Spelling Numbers Star Wars GPT Star Wars Opening Crawl Sudoku Sudoku (Fill-in) Ten-pin Bowling Tic-tac-toe Time Distance Tongue-twisters Topological Sort Tower of Hanoi Transpose Sentence Trinomial Triangle United States Vampire Numbers Van Eck Sequence Zeckendorf Representation Zodiac Signs γ λ π τ φ √2 𝑒 Experimental Hole Alphabetic Numbers Apéry’s Constant Binary Lambda Calculus Connect Four Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Rectangle Fill Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial # Golfer Points Chars Time Submitted 401st BREMAUCY 🇫🇷 502 99 61ms 4 Nov 2025 402nd jameswmccarty 502 160 18ms 27 Mar 2025 403rd aksyristos 497 100 62ms 27 hours ago 404th didion0 🇺🇸 497 181 22ms 30 May 2025 404th JOrE20 497 181 13ms 2 Dec 2025 406th snoozingnewt 🇨🇦 492 101 46ms 30 Oct 2025 407th CaedenHarper 🇨🇦 489 184 19ms 30 Aug 2025 408th helbling 🇨🇭 481 187 12ms 26 Mar 2025 409th TheZwierzLF 🇵🇱 479 168 25ms 24 Dec 2025 410th msbranicky 476 169 22ms 26 Mar 2025 411th targrik 474 206 543ms 4 Jul 2025 412th Protothor 473 190 17ms 26 Jul 2025 413th MeWhenI 🇻🇦 470 245 392ms 5 Apr 2025 414th TheZwierzLF 🇵🇱 467 159 616ms 14 Dec 2025 415th Apataras 467 344 417ms 23 Jul 2025 416th DialFrost 🇸🇬 464 107 64ms 26 Mar 2025 417th CLOStrophobic 🇮🇹 457 176 26ms 14 Apr 2025 418th ZakkkkAttackkkk 🇵🇭 454 177 48ms 15 Feb 2026 419th CaedenHarper 🇨🇦 453 254 405ms 17 Oct 2025 420th coldham10 452 178 29ms 28 Jun 2025 421st snoozingnewt 🇨🇦 451 345 253ms 30 Oct 2025 422nd snoozingnewt 🇨🇦 447 314 35ms 30 Oct 2025 423rd ericlangedijk 🇸🇮 446 258 450ms 3 Apr 2025 424th IISResetMe 444 177 3,593ms 26 Mar 2025 425th snoozingnewt 🇨🇦 440 365 520ms 30 Oct 2025 426th snoozingnewt 🇨🇦 436 193 24ms 30 Oct 2025 427th gigaprofisi 🇺🇸 434 207 41ms 7 Aug 2025 428th yoshykai 433 371 462ms 10 Apr 2025 429th snoozingnewt 🇨🇦 432 208 13ms 30 Oct 2025 430th vhoulbreque 🇫🇷 425 189 128ms 12 Nov 2025 431st snoozingnewt 🇨🇦 424 271 467ms 30 Oct 2025 432nd Alban-Boissard 423 190 26ms 14 Jun 2025 432nd CatsAreFluffy 423 190 21ms 30 Oct 2025 432nd tomh1012 423 190 39ms 10 days ago 435th guilhem-roy 🇫🇷 419 192 30ms 22 Nov 2025 436th acollett89 416 216 11ms 5 Aug 2025 437th snoozingnewt 🇨🇦 409 239 13ms 30 Oct 2025 438th BREMAUCY 🇫🇷 408 311 130ms 16 Apr 2025 439th RobertHoeh 402 200 26ms 19 Apr 2025 440th snoozingnewt 🇨🇦 402 304 639ms 30 Oct 2025 441st kasarino 394 292 468ms 27 Feb 2026 442nd undefinedRyan 392 205 53ms 19 Apr 2025 442nd asherdiamond 392 205 19ms 13 Aug 2025 444th Robvdhout 387 232 13ms 10 Apr 2025 445th MeWhenI 🇻🇦 378 219 1,830ms 15 Sep 2025 446th snoozingnewt 🇨🇦 371 415 51ms 30 Oct 2025 447th MeWhenI 🇻🇦 370 283 3,135ms 19 Jun 2025 448th zakariamouhid 368 244 15ms 17 Jun 2025 449th iczelia 🇩🇪 364 247 16ms 25 Oct 2025 450th snoozingnewt 🇨🇦 363 556 30ms 30 Oct 2025 451st mbittner20 357 225 15ms 1 Apr 2025 452nd KatieLG 🇬🇧 351 738 476ms 1 Mar 2026 453rd YAJUE114514 347 232 21ms 1 Jul 2025 454th snoozingnewt 🇨🇦 345 193 26ms 30 Oct 2025 455th brimstonetrader 345 233 35ms 1 Apr 2025 456th snoozingnewt 🇨🇦 345 368 3ms 30 Oct 2025 457th razdiamond 335 240 19ms 5 Aug 2025 458th Vaekor 323 249 16ms 5 Apr 2025 459th snoozingnewt 🇨🇦 319 417 75ms 30 Oct 2025 460th dokutan 318 156 77ms 9 Apr 2025 461st snoozingnewt 🇨🇦 313 385 45ms 30 Oct 2025 462nd DitherDude 310 371 450ms 9 Apr 2025 463rd ravnskjaer 🇩🇰 274 587 474ms 15 Dec 2025 464th mwessler 266 250 17ms 28 Mar 2025 465th WillowWispy 264 305 57ms 28 Mar 2025 466th FortuiteMan 🇫🇷 245 2,608 4,262ms 8 Aug 2025 467th Zhenyu-Bo 241 333 15ms 1 Aug 2025 468th JOrE20 224 900 58ms 20 Feb 2026 469th Msleizak 🇫🇷 221 356 1,866ms 19 May 2025 470th jb567 170 472 38ms 13 Apr 2025 471st AidanWalter 140 576 13ms 28 Nov 2025 472nd kg583 🇺🇸 0 14 2,437ms 14 May 2025 473rd namelessiw 0 20 813ms 26 Nov 2025 474th saito-ta 🇯🇵 0 22 102ms 8 Jul 2025 475th darrenks 🇺🇸 0 25 93ms 7 Jul 2025 476th GolfingSuccess 🇬🇷 0 28 317ms 13 Aug 2025 476th aditsu 0 28 173ms 21 Sep 2025 478th plcc0 0 33 168ms 9 May 2025 478th 2bular 0 33 66ms 9 May 2025 480th maweowo 🇩🇪 0 34 56ms 30 Sep 2025 First Prev 401–480 of 492 Next Last