The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 2 days. Why not try and solve them ahead of time?
Reversi 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 241st sisyphus-ppcg 🇦🇺 689 74 5ms 1 Jun 2024 241st SirBogman 🇺🇸 689 74 6ms 2 Jun 2024 243rd albanian-laundromat 689 117 410ms 21 days ago 244th albanian-laundromat 687 348 1,923ms 27 Nov 2025 245th dcgjb 684 113 1,565ms 4 Jun 2024 246th adyache 🇺🇸 683 325 829ms 21 Jun 2024 247th Shanethegamer 🇺🇸 682 221 1,349ms 1 Jun 2024 248th Yewzir 🇧🇪 681 301 1,910ms 9 Jun 2024 249th primo-ppcg 🇹🇭 680 75 22ms 23 Jan 2025 250th albanian-laundromat 680 117 59ms 17 Nov 2025 251st Shanethegamer 🇺🇸 679 352 1,605ms 10 Apr 2025 252nd error256 678 97 36ms 1 Jun 2024 253rd Shanethegamer 🇺🇸 676 240 228ms 14 Jun 2024 254th MeWhenI 🇻🇦 673 131 36ms 13 Aug 2024 255th Yax42 🇫🇷 672 146 26ms 20 Jan 2026 256th mousetail 🇳🇱 670 183 2ms 23 Sep 2025 256th madex 🇩🇪 670 183 2ms 23 Dec 2025 258th ovs-code 🇩🇪 666 121 535ms 2 Jul 2024 259th Yewzir 🇧🇪 665 286 322ms 9 Jun 2024 260th Shanethegamer 🇺🇸 663 148 13ms 12 Jun 2024 261st MeWhenI 🇻🇦 661 122 521ms 1 Jun 2024 262nd MeWhenI 🇻🇦 661 205 513ms 1 Jun 2024 263rd Shanethegamer 🇺🇸 661 235 12ms 13 Jun 2024 264th blaztoma 🇱🇹 658 100 41ms 18 days ago 265th Shanethegamer 🇺🇸 658 214 162ms 1 Jun 2024 266th orthoplex 🇨🇽 657 121 22ms 1 Jun 2024 267th rucin93 🇵🇱 655 129 153ms 31 Oct 2024 268th Shanethegamer 🇺🇸 655 207 494ms 12 Jun 2024 269th scpchicken 🇵🇼 654 78 7ms 3 Jun 2024 269th blaztoma 🇱🇹 654 78 6ms 12 Jan 2026 271st nwellnhof 🇩🇪 652 122 18ms 1 Jun 2024 271st MeWhenI 🇻🇦 652 122 26ms 7 Jun 2024 271st sisyphus-ppcg 🇦🇺 652 122 19ms 25 Jul 2024 274th MeWhenI 🇻🇦 652 216 130ms 1 Jun 2024 275th KasperKivimaeki 🇫🇮 648 189 3ms 3 Sep 2025 276th kritixilithos 647 114 35ms 1 Jun 2024 276th error256 647 114 32ms 16 Jun 2024 276th MeWhenI 🇻🇦 647 114 36ms 15 Jul 2025 279th ovs-code 🇩🇪 647 123 18ms 1 Jun 2024 279th ryyyn 🇺🇸 647 123 19ms 5 Nov 2025 281st MeWhenI 🇻🇦 646 79 7ms 1 Jun 2024 282nd namelessiw 646 208 502ms 16 Oct 2025 283rd xsot 🇸🇬 645 125 508ms 2 Jun 2024 283rd SirBogman 🇺🇸 645 125 503ms 2 Jun 2024 285th KatieLG 🇬🇧 640 126 2,638ms 6 Oct 2025 286th MostParsingVex 640 210 466ms 5 days ago 287th Shanethegamer 🇺🇸 637 216 485ms 7 Jun 2024 288th ovs-code 🇩🇪 636 116 32ms 1 Jun 2024 288th retrohun 636 116 35ms 7 Jun 2024 290th edsrzf 🇳🇿 636 125 18ms 9 Dec 2025 291st helbling 🇨🇭 633 155 16ms 1 Jun 2024 292nd 5cw 🇺🇸 631 126 18ms 1 Jun 2024 292nd stefangimmillaro 631 126 18ms 30 Jan 2025 292nd bricknellj 631 126 18ms 6 Feb 2025 292nd KatieLG 🇬🇧 631 126 2,449ms 15 Sep 2025 292nd Flekay 🇩🇪 631 126 16ms 15 Feb 2026 297th error256 622 238 4,428ms 15 Apr 2025 298th AlephSquirrel 621 128 30ms 4 Jun 2024 299th MeWhenI 🇻🇦 619 157 10ms 20 Jun 2024 300th ndren 617 129 304ms 11 Jul 2025 301st ovs-code 🇩🇪 617 137 174ms 17 Apr 2025 302nd emgordon154 616 150 11ms 10 Dec 2024 303rd Shanethegamer 🇺🇸 615 158 9ms 13 Jun 2024 304th GrayJoKing 🇦🇺 612 138 163ms 14 Aug 2024 304th error256 612 138 167ms 6 May 2025 306th AlephSquirrel 611 225 38ms 21 Oct 2024 307th MeWhenI 🇻🇦 609 255 6ms 10 Jun 2024 308th MeWhenI 🇻🇦 606 219 7ms 10 Jun 2024 309th retrohun 600 202 182ms 19 Aug 2024 310th galloj 🇨🇿 599 123 28ms 9 Jun 2024 311th Shanethegamer 🇺🇸 599 189 600ms 12 Jun 2024 312th jatloe 598 133 362ms 28 Oct 2024 313th stefangimmillaro 595 124 35ms 12 Nov 2025 314th GolfingSuccess 🇬🇷 594 134 20ms 1 Jun 2024 315th Shanethegamer 🇺🇸 594 203 368ms 13 Jun 2024 316th MeWhenI 🇻🇦 592 295 36ms 12 Jul 2025 317th MeWhenI 🇻🇦 591 204 486ms 27 Jul 2024 318th bizy-coder 589 137 569ms 1 Jun 2024 319th Shanethegamer 🇺🇸 588 234 39ms 4 Oct 2024 320th bzijlema 🇳🇱 585 136 36ms 14 Jan 2026 First Prev 241–320 of 464 Next Last