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?
Roman to Arabic 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 561st AlephSquirrel 726 138 5ms 29 Jul 2023 562nd treeowl 726 153 312ms 25 Feb 2019 563rd MeWhenI 🇻🇦 725 98 3,238ms 24 Oct 2024 564th MeWhenI 🇻🇦 724 128 34ms 10 Oct 2023 565th o0lit3 🇺🇸 722 61 28ms 27 Sep 2020 565th Lydxn 🇨🇦 722 61 165ms 31 Dec 2021 565th DialFrost 🇸🇬 722 61 168ms 25 Jan 2023 565th ovs-code 🇩🇪 722 61 165ms 3 Oct 2023 565th iczelia 🇩🇪 722 61 183ms 5 Nov 2025 565th blaztoma 🇱🇹 722 61 165ms 22 Nov 2025 571st Waffle3z 722 124 18ms 17 Apr 2022 572nd laikoni 722 154 315ms 23 Feb 2019 573rd prplz 🇦🇺 720 81 973ms 17 Jun 2020 573rd Feniske 🇫🇷 720 81 2,794ms 26 Nov 2023 575th xyangst 720 105 18ms 4 Oct 2024 575th Salutations45 720 105 18ms 11 Jan 2025 577th DialFrost 🇸🇬 720 138 40ms 31 Dec 2025 578th ndren 719 90 531ms 5 May 2024 578th DialFrost 🇸🇬 719 90 517ms 4 Jun 2024 580th inventshah 719 100 20ms 14 Apr 2021 580th lynn 719 100 20ms 29 Nov 2021 580th CedricGebistorf 719 100 21ms 2 Mar 2022 580th scpchicken 🇵🇼 719 100 21ms 4 May 2022 580th AlephSquirrel 719 100 27ms 6 Dec 2022 580th bricknellj 719 100 21ms 25 Jan 2023 580th LogicalJoe 719 100 18ms 24 May 2023 580th janbehrens 🇩🇪 719 100 20ms 17 Jun 2023 580th bizy-coder 719 100 22ms 27 Jan 2024 580th 5cw 🇺🇸 719 100 19ms 5 Jul 2024 580th firegene 🇮🇪 719 100 19ms 30 Jan 2025 580th edsrzf 🇳🇿 719 100 20ms 29 Jun 2025 580th KasperKivimaeki 🇫🇮 719 100 21ms 30 Jun 2025 580th wuduculfre 719 100 20ms 22 Jul 2025 580th StefanHabel 🇨🇦 719 100 20ms 24 days ago 595th Shanethegamer 🇺🇸 715 139 39ms 30 Jun 2022 596th Shanethegamer 🇺🇸 714 88 4ms 30 Oct 2023 597th Attero 🇸🇪 714 106 14ms 28 Oct 2020 597th jared-hughes 714 106 16ms 3 Aug 2022 597th coreynash 714 106 18ms 16 Feb 2024 600th antimon2 🇯🇵 712 83 1,189ms 18 Aug 2025 601st mrondon8 712 101 21ms 5 Sep 2021 601st Artemis21 🇬🇧 712 101 19ms 10 Jan 2025 601st blaztoma 🇱🇹 712 101 21ms 19 Dec 2025 604th HPWiz 🇳🇿 711 48 41ms 4 Oct 2021 605th AlephSquirrel 711 91 526ms 21 Jan 2024 605th Jacob385 711 91 450ms 13 Nov 2024 607th Shanethegamer 🇺🇸 711 115 1,069ms 30 Oct 2023 608th ovs-code 🇩🇪 709 92 163ms 20 Nov 2024 608th dokutan 709 92 165ms 20 Apr 2025 610th raphaelimahorn 707 107 19ms 17 Aug 2021 610th scpchicken 🇵🇼 707 107 14ms 26 Jan 2022 610th itsh01 707 107 14ms 3 Apr 2022 610th solmyr2000 707 107 14ms 11 Jun 2022 610th rifatx 707 107 16ms 17 Mar 2023 610th acollett89 707 107 13ms 4 Aug 2025 616th Attero 🇸🇪 705 102 23ms 25 Sep 2020 616th gresm 705 102 21ms 23 days ago 618th user189032 703 158 296ms 30 May 2019 619th Yewzir 🇧🇪 702 172 44ms 9 Jun 2024 620th Alessandro-Balconi 🇮🇹 699 49 92ms 14 Jul 2023 620th Shanethegamer 🇺🇸 699 49 85ms 7 Dec 2024 622nd lynn 699 117 1,077ms 30 Nov 2021 623rd strout 699 159 331ms 14 Dec 2023 624th andersk 🇺🇸 699 162 155ms 18 Mar 2020 625th HumanoidCPU 698 103 19ms 7 Jun 2024 626th m-tkach 🇺🇦 698 117 4ms 21 Jan 2022 627th primo-ppcg 🇹🇭 697 145 485ms 1 Jun 2020 628th ovs-code 🇩🇪 696 86 20ms 4 Oct 2024 629th CaedenHarper 🇨🇦 695 85 232ms 22 Aug 2025 630th emgordon154 695 93 402ms 24 Sep 2024 631st CaedenHarper 🇨🇦 695 160 255ms 22 Aug 2025 632nd SirBogman 🇺🇸 694 84 3,606ms 18 May 2024 633rd DialFrost 🇸🇬 694 94 172ms 4 Aug 2024 634th jake-freeman 694 109 15ms 13 May 2020 634th ArmaanAS 694 109 18ms 7 Mar 2021 634th voytxt 🇨🇿 694 109 19ms 12 Jul 2024 634th Lv0Sys 🇵🇱 694 109 15ms 20 Feb 2026 638th CaedenHarper 🇨🇦 694 129 6ms 22 Aug 2025 639th emgordon154 693 111 2,257ms 13 Dec 2024 640th Yewzir 🇧🇪 693 130 472ms 15 Nov 2025 First Prev 561–640 of 1,509 Next Last