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 641st NewDefectus 🇮🇱 691 104 20ms 16 Oct 2021 642nd Shanethegamer 🇺🇸 691 113 390ms 31 Oct 2023 643rd stefangimmillaro 690 113 8ms 7 Nov 2023 644th helbling 🇨🇭 688 110 19ms 3 Sep 2025 645th Shanethegamer 🇺🇸 688 146 2,945ms 9 Jan 2022 645th Yewzir 🇧🇪 688 146 60ms 10 Jun 2024 647th blaztoma 🇱🇹 686 70 44ms 22 Nov 2025 648th rucin93 🇵🇱 686 95 168ms 31 Oct 2024 649th Yewzir 🇧🇪 686 135 11ms 9 Jun 2024 650th yzhs 🇩🇪 686 162 298ms 25 Jul 2021 651st Yewzir 🇧🇪 686 186 94ms 6 days ago 652nd yzhs 🇩🇪 685 105 19ms 25 Oct 2020 652nd Espiobest 685 105 27ms 26 Feb 2021 652nd mokymok 🇺🇸 685 105 22ms 27 Sep 2021 655th Natanaelel 🇸🇪 683 73 226ms 16 Feb 2023 656th XenThe 🇬🇧 682 111 14ms 1 Jul 2025 657th CaedenHarper 🇨🇦 681 136 11ms 22 Aug 2025 658th annaproxy 681 157 32ms 11 May 2023 659th saito-ta 🇯🇵 677 87 537ms 23 Oct 2023 660th MeWhenI 🇻🇦 676 147 45ms 17 Feb 2023 661st mintypython 675 112 13ms 16 Oct 2018 661st saramaebee 675 112 15ms 18 Oct 2018 661st taklam 675 112 15ms 4 Jul 2020 661st igmcdowell 675 112 13ms 4 Jan 2022 665th ReidZ3 🇺🇸 674 165 319ms 13 Dec 2020 666th Jiramide 673 133 13ms 7 Feb 2021 667th DialFrost 🇸🇬 672 106 524ms 16 Nov 2024 668th SirBogman 🇺🇸 669 51 44ms 1 Sep 2022 669th DialFrost 🇸🇬 669 88 3,026ms 7 Oct 2024 670th vmcnabb 🇳🇿 669 113 14ms 6 May 2021 670th targrik 669 113 14ms 24 Feb 2025 672nd sean-niemann 🇺🇸 669 122 3ms 31 Oct 2023 673rd clockworknazo 668 114 21ms 20 Feb 2023 674th dokutan 668 138 250ms 13 Nov 2025 675th MichalMarsalek 🇨🇿 667 135 379ms 30 Aug 2022 676th MahlerFive 🇨🇦 667 186 375ms 24 Apr 2020 677th AlephSquirrel 666 55 4ms 8 Nov 2025 678th FlorianCassayre 🇫🇷 666 108 23ms 18 Sep 2023 679th Natanaelel 🇸🇪 666 167 305ms 10 May 2025 680th MeWhenI 🇻🇦 666 271 143ms 29 Nov 2023 681st alexkunin 664 114 13ms 7 Jul 2019 682nd lionbryce 663 135 10ms 8 Aug 2024 683rd SirBogman 🇺🇸 663 182 43ms 17 Apr 2022 684th frankgraziano 662 89 3,631ms 13 Feb 2026 685th RaBa21 🇭🇺 660 109 20ms 12 Jul 2025 686th Yax42 🇫🇷 658 115 17ms 21 Jan 2026 687th KasperKivimaeki 🇫🇮 658 137 492ms 7 Nov 2025 688th Bubbler-4 657 52 41ms 9 Dec 2021 688th DialFrost 🇸🇬 657 52 42ms 1 Feb 2023 690th sean-niemann 🇺🇸 657 153 57ms 11 Jul 2024 691st Shanethegamer 🇺🇸 656 76 142ms 12 Dec 2021 692nd dvargas46 🇺🇸 655 90 209ms 23 Jan 2023 693rd varhammer 655 121 157ms 13 Dec 2023 694th SB-945 654 110 29ms 7 Apr 2024 694th Troon 654 110 27ms 27 Aug 2025 696th dokutan 653 137 12ms 20 Apr 2025 697th BBoehm 🇩🇪 652 116 14ms 21 Dec 2020 698th hyvyys 647 117 14ms 19 Sep 2020 698th aksyristos 647 117 13ms 2 Nov 2022 700th 386asm 🇺🇸 646 154 44ms 5 May 2023 701st edsrzf 🇳🇿 645 118 41ms 12 Nov 2025 702nd villfa 645 121 16ms 2 Nov 2018 702nd janbehrens 🇩🇪 645 121 407ms 16 May 2023 704th Shanethegamer 🇺🇸 643 127 4ms 28 May 2025 705th keelimeguy 🇺🇸 642 112 24ms 17 May 2025 706th user189032 641 118 15ms 29 May 2019 707th Shanethegamer 🇺🇸 641 120 20ms 17 Dec 2023 708th SirBogman 🇺🇸 640 101 597ms 20 Jan 2024 709th Yewzir 🇧🇪 640 122 422ms 10 Jun 2024 710th scpchicken 🇵🇼 639 78 173ms 4 May 2022 711th RockOfStone 639 140 11ms 17 Mar 2024 712th mrondon8 639 158 613ms 5 Sep 2021 713th unfinishedprogram 636 119 14ms 12 Jul 2024 714th snyderek 🇺🇸 636 158 60ms 9 Nov 2024 715th MeWhenI 🇻🇦 635 101 1,372ms 15 Sep 2025 716th jared-hughes 635 141 11ms 16 Apr 2022 717th CaedenHarper 🇨🇦 635 142 159ms 18 Aug 2025 718th olligobber 🇦🇺 635 175 291ms 21 May 2020 719th MeWhenI 🇻🇦 632 58 6ms 16 Jan 2022 720th stordev 631 114 21ms 26 Feb 2021 First Prev 641–720 of 1,509 Next Last