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 720th robin-scragg 631 114 22ms 24 Aug 2025 722nd PatrickStephansen 🇿🇦 630 120 27ms 9 Jun 2021 722nd stefangabos 🇷🇴 630 120 20ms 13 Sep 2022 724th targrik 629 124 19ms 2 days ago 725th HumanoidCPU 628 103 466ms 7 Jun 2024 726th janbehrens 🇩🇪 628 160 75ms 18 May 2023 727th Jiramide 628 177 296ms 8 Feb 2021 728th janbehrens 🇩🇪 627 161 549ms 16 May 2023 729th jupj 🇫🇮 623 131 3ms 27 Aug 2022 729th plcc0 623 131 4ms 24 days ago 731st MeWhenI 🇻🇦 621 105 181ms 3 Aug 2024 732nd YAJUE114514 621 179 292ms 3 Aug 2025 733rd primo-ppcg 🇹🇭 620 95 1,780ms 17 Apr 2022 734th chartung17 620 116 23ms 1 Jan 2024 735th CaedenHarper 🇨🇦 616 78 42ms 18 Aug 2025 736th jacklynnepenick 615 117 21ms 13 Aug 2021 736th JunkIce 615 117 27ms 24 Nov 2024 738th sebipopa 🇷🇴 615 123 17ms 14 Sep 2022 739th jared-hughes 614 96 397ms 23 Jul 2023 740th CaedenHarper 🇨🇦 614 116 521ms 17 Aug 2025 741st Yewzir 🇧🇪 614 133 4ms 10 Jun 2024 742nd neihousaigaai 610 124 16ms 28 Apr 2021 742nd Andrey-Plotnikov 610 124 14ms 9 Aug 2025 744th Shanethegamer 🇺🇸 610 130 29ms 4 Oct 2024 745th vezzick 609 118 21ms 5 Mar 2021 745th CommandLeo 🇮🇹 609 118 225ms 22 Nov 2025 745th Lv0Sys 🇵🇱 609 118 19ms 20 Feb 2026 748th olivermrose 🇺🇸 608 79 82ms 24 Oct 2021 749th retrohun 607 111 15ms 21 Sep 2024 750th albanian-laundromat 606 106 1,983ms 26 Oct 2025 751st dsntzn 🇸🇰 605 125 16ms 1 Mar 2021 751st smclaughlin-cf 605 125 16ms 8 Apr 2025 753rd TomvdPeet 605 129 30ms 7 Dec 2025 754th bzijlema 🇳🇱 604 119 21ms 3 Jul 2024 755th MeWhenI 🇻🇦 604 193 36ms 6 Jun 2023 756th cure-honey 🇯🇵 603 200 43ms 26 Apr 2020 757th Phil-RGOMEGA 601 149 8ms 30 Aug 2023 758th KatieLG 🇬🇧 600 67 48ms 27 Nov 2023 759th ollyspooner 600 126 16ms 18 Oct 2023 760th giacomogallina 599 120 21ms 21 May 2020 761st MeWhenI 🇻🇦 598 105 24ms 12 Nov 2022 762nd albanian-laundromat 598 178 40ms 22 Aug 2025 763rd snoozingnewt 🇨🇦 597 164 125ms 20 Nov 2025 764th eranws 596 127 14ms 9 Sep 2022 765th CaedenHarper 🇨🇦 596 131 432ms 17 Aug 2025 766th DialFrost 🇸🇬 596 133 31ms 11 Dec 2024 767th timvermeulen 596 190 157ms 4 Jan 2020 768th Shanethegamer 🇺🇸 595 74 6ms 6 Jan 2022 769th ovs-code 🇩🇪 595 128 20ms 4 Feb 2023 770th dokutan 592 132 392ms 7 Apr 2025 771st filharmonista 592 138 3ms 13 Mar 2020 771st TeodorDyakov 🇧🇬 592 138 3ms 3 Jul 2025 773rd sisyphus-ppcg 🇦🇺 591 114 221ms 24 Jun 2022 774th elisherer 🇮🇱 591 128 22ms 24 Apr 2019 774th avartanii 591 128 21ms 17 Jan 2021 774th MathisBullinger 591 128 24ms 15 Nov 2021 777th OllieBoyne 🇬🇧 589 122 21ms 3 Jun 2021 777th Emutis 🇱🇹 589 122 19ms 17 Sep 2025 779th SirBogman 🇺🇸 587 75 20ms 3 Jan 2022 780th timvermeulen 587 167 124ms 19 Jan 2020 781st lynn 587 182 20ms 18 Nov 2021 782nd ian-odonnell 586 129 16ms 9 Mar 2018 782nd JohnSBarden 586 129 13ms 9 Nov 2021 784th CaedenHarper 🇨🇦 586 135 115ms 18 Aug 2025 785th rowechenzhong 585 123 21ms 25 Mar 2020 785th MichalMarsalek 🇨🇿 585 123 23ms 9 Oct 2022 785th qpwoeirut 585 123 22ms 20 Nov 2025 785th zhaohm14 585 123 19ms 9 Jan 2026 789th mtirado1 585 153 7ms 18 Apr 2023 790th ian-h-chamberlain 🇺🇸 584 194 156ms 6 Jan 2020 791st janbehrens 🇩🇪 583 140 4ms 18 May 2023 792nd KatieLG 🇬🇧 583 168 773ms 15 Jan 2023 793rd SirBogman 🇺🇸 583 403 81ms 23 Nov 2022 794th omurakazuaki 🇯🇵 582 130 14ms 16 Feb 2021 795th madex 🇩🇪 581 155 457ms 14 days ago 796th emgordon154 580 336 1,614ms 6 Nov 2025 797th not-a-pokemon 579 141 4ms 9 Sep 2025 798th p01 577 131 22ms 7 Feb 2018 798th Florian-Mt 577 131 18ms 23 Oct 2023 800th JRaspass 🇬🇧 577 132 10ms 1 Oct 2022 First Prev 721–800 of 1,509 Next Last