The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 3 days. Why not try and solve them ahead of time?
Arabic to Roman 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 801st MeWhenI 🇻🇦 581 129 63ms 13 Feb 2025 802nd revlayle 🇺🇸 581 205 406ms 21 Nov 2021 803rd Shanethegamer 🇺🇸 581 232 458ms 28 Jan 2024 804th janbehrens 🇩🇪 580 133 1,008ms 1 Nov 2021 805th unfinishedprogram 580 150 15ms 19 Jan 2024 806th nsprd 580 164 202ms 16 Jan 2024 807th mtirado1 580 200 6ms 25 Dec 2022 808th stefangimmillaro 579 105 45ms 23 Feb 2023 809th neel11235813 579 135 577ms 12 Mar 2024 810th eMGeeneer 579 250 519ms 26 Jun 2024 811th CaedenHarper 🇨🇦 579 266 311ms 17 Nov 2025 812th betaveros 578 149 20ms 2 Jan 2023 812th sultan 578 149 1,849ms 9 Mar 2024 814th blaztoma 🇱🇹 578 197 3,232ms 1 Nov 2025 815th roavin 578 233 74ms 7 Jan 2022 816th Tezaruz 576 151 18ms 20 Dec 2023 816th itserasmus 576 151 22ms 25 Jan 2024 816th olleicua 🇺🇸 576 151 16ms 16 Feb 2024 819th YouLookLikeYouNeedAMonkey 576 234 476ms 14 Oct 2022 820th daedals 574 150 20ms 12 Jun 2019 820th abailey2020 🇺🇸 574 150 21ms 13 Dec 2020 822nd MeWhenI 🇻🇦 574 166 1,142ms 16 Jun 2023 823rd edsrzf 🇳🇿 574 172 16ms 19 Sep 2024 824th omurakazuaki 🇯🇵 572 152 14ms 15 Feb 2021 824th biocommando 🇫🇮 572 152 19ms 19 Aug 2023 824th hacker112 🇸🇪 572 152 15ms 19 Jun 2024 824th eTrey13 572 152 15ms 3 Feb 2025 824th SOONwasTaken 572 152 14ms 1 Oct 2025 829th Daniikk1012 571 111 40ms 3 Nov 2025 830th alemelis 571 135 814ms 19 Sep 2024 831st alphafalfa 571 166 24ms 1 Aug 2025 832nd mauro-1 🇮🇹 570 151 23ms 19 Aug 2021 832nd prplz 🇦🇺 570 151 994ms 5 Oct 2021 832nd knutae 🇳🇴 570 151 20ms 30 Nov 2021 832nd shelerr 570 151 22ms 4 Jul 2023 832nd LandonWeng 570 151 19ms 30 Sep 2025 832nd CommandLeo 🇮🇹 570 151 36ms 22 Dec 2025 838th ms0rgn 570 167 203ms 2 May 2018 839th jared-hughes 570 179 10ms 4 Apr 2022 840th sultan 570 254 535ms 15 Apr 2022 841st Ivraj 569 153 17ms 10 Aug 2021 841st daveberlin 569 153 16ms 6 Nov 2023 843rd albanian-laundromat 568 214 142ms 5 Jul 2025 844th DialFrost 🇸🇬 567 136 471ms 25 May 2024 845th rzv-me 567 174 14ms 5 Oct 2024 846th ericlangedijk 🇸🇮 567 210 463ms 18 Mar 2022 847th m-tkach 🇺🇦 566 138 475ms 25 Jan 2024 848th NewDefectus 🇮🇱 566 152 21ms 8 Oct 2021 848th stefangimmillaro 566 152 32ms 26 Dec 2022 848th tsidwick 566 152 21ms 20 Dec 2023 848th gallium-gonzollium 566 152 37ms 2 Nov 2024 848th blaztoma 🇱🇹 566 152 19ms 11 Oct 2025 853rd neihousaigaai 566 256 653ms 27 Apr 2021 854th jacobly0 🇺🇸 566 388 1,738ms 22 Apr 2024 855th user189032 565 154 17ms 29 May 2019 855th ernestd 565 154 23ms 21 Jan 2021 855th junkondo-jp 565 154 37ms 6 May 2024 858th Phil-RGOMEGA 565 205 8ms 2 Jun 2023 859th dokutan 565 291 181ms 29 Mar 2025 860th GrayJoKing 🇦🇺 565 296 11ms 11 Aug 2020 861st lacroixjonathan87 564 175 17ms 7 Aug 2020 862nd lynn 563 153 836ms 4 Mar 2021 862nd test-user1337 563 153 22ms 29 Aug 2023 864th arctouch-cristiannevianna 562 212 440ms 1 Mar 2024 865th MattShaile 561 155 20ms 21 Mar 2022 865th omgmog 561 155 16ms 8 Aug 2022 867th kkoenig 561 182 10ms 23 Dec 2023 868th nullie 559 154 30ms 7 Jun 2022 869th jjstreet 559 259 659ms 24 Nov 2020 870th Stockoh 🇫🇷 558 140 553ms 15 Jun 2024 871st MeWhenI 🇻🇦 557 204 578ms 1 Feb 2024 872nd anonymaew 555 155 22ms 19 Aug 2023 872nd mathb0y512 555 155 20ms 11 Jan 2024 874th nat-418 554 165 16ms 3 Nov 2022 875th MeWhenI 🇻🇦 554 265 58ms 16 Jun 2023 876th denkyuu1 553 110 44ms 44 hours ago 877th OllieBoyne 🇬🇧 552 156 22ms 27 Jan 2021 877th chartung17 552 156 18ms 1 Jan 2024 877th ZorblaxV 552 156 20ms 10 Jan 2025 880th Shanethegamer 🇺🇸 552 185 10ms 28 Jan 2024 First Prev 801–880 of 1,907 Next Last