The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 26 hours. 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 321st bzijlema 🇳🇱 585 136 36ms 14 Jan 2026 322nd tatzyr 🇯🇵 582 113 163ms 26 Mar 2025 323rd Shanethegamer 🇺🇸 582 231 447ms 24 Sep 2025 324th CaedenHarper 🇨🇦 581 327 325ms 20 Nov 2025 325th MeWhenI 🇻🇦 580 145 1,293ms 15 Sep 2025 326th blaztoma 🇱🇹 576 138 25ms 11 Dec 2025 326th Lv0Sys 🇵🇱 576 138 25ms 23 Feb 2026 328th Shanethegamer 🇺🇸 574 202 131ms 13 Jun 2024 329th bizy-coder 572 139 32ms 1 Jun 2024 329th cros107 🇦🇺 572 139 31ms 19 Jun 2024 331st edsrzf 🇳🇿 572 241 48ms 4 Apr 2025 332nd bac0id 572 259 80ms 24 Jun 2024 333rd JOrE20 570 172 46ms 12 Feb 2026 334th Yewzir 🇧🇪 569 233 7ms 9 Jun 2024 334th rucin93 🇵🇱 569 233 43ms 8 Dec 2025 336th davecame 568 140 20ms 16 Jul 2024 336th Emutis 🇱🇹 568 140 25ms 12 Dec 2025 338th error256 567 90 6ms 4 Sep 2024 339th D-MOVE 🇵🇭 567 116 65ms 4 Feb 2026 340th snoozingnewt 🇨🇦 559 252 131ms 20 Nov 2025 341st dokutan 554 133 30ms 15 Aug 2024 342nd Shanethegamer 🇺🇸 554 189 6ms 28 Sep 2024 343rd Shanethegamer 🇺🇸 551 152 1,408ms 1 Jun 2024 344th Yewzir 🇧🇪 549 268 212ms 9 Jun 2024 345th MeWhenI 🇻🇦 545 155 161ms 3 Aug 2024 346th Lv0Sys 🇵🇱 545 349 315ms 11 Dec 2025 347th Shanethegamer 🇺🇸 540 171 84ms 13 Jun 2024 348th dokutan 539 182 14ms 15 Jun 2025 349th dokutan 537 172 16ms 1 Jul 2024 350th dokutan 529 159 1,642ms 30 Aug 2025 351st OllieBoyne 🇬🇧 527 151 29ms 6 Jun 2024 352nd jerrandolph 524 363 326ms 29 Sep 2025 353rd commandz0 🇺🇸 523 152 26ms 3 Jun 2024 354th wh3n3v3r 🇨🇿 520 153 52ms 12 Nov 2024 355th bac0id 517 237 2ms 24 Jun 2024 356th Yax42 🇫🇷 515 261 508ms 16 Oct 2025 357th dokutan 514 157 496ms 16 days ago 358th msbranicky 511 372 314ms 14 Aug 2024 359th ZakkkkAttackkkk 🇵🇭 503 158 43ms 9 Feb 2026 359th dokutan 503 158 19ms 16 days ago 361st olleicua 🇺🇸 498 132 43ms 25 Feb 2025 362nd MeWhenI 🇻🇦 497 186 18ms 10 Jun 2024 363rd dokutan 494 171 146ms 21 Jun 2025 364th h3ra993huskp 🇯🇵 490 274 611ms 30 Nov 2025 365th StefanHabel 🇨🇦 488 163 330ms 4 days ago 366th Shanethegamer 🇺🇸 485 228 5ms 13 Jun 2024 367th Shanethegamer 🇺🇸 484 136 46ms 1 Jun 2024 368th mousetail 🇳🇱 482 183 22ms 27 Sep 2024 369th Yewzir 🇧🇪 482 371 26ms 9 Jun 2024 370th Yewzir 🇧🇪 481 323 6ms 9 Jun 2024 371st msbranicky 477 278 8ms 11 Aug 2024 372nd bac0id 477 284 405ms 24 Jun 2024 373rd EnTerr 473 168 19ms 5 Jun 2024 374th msbranicky 467 315 223ms 14 Aug 2024 375th anter69 🇭🇺 465 171 28ms 20 Feb 2026 376th dokutan 463 290 435ms 24 Sep 2025 377th Yewzir 🇧🇪 463 293 505ms 22 Dec 2024 378th ahmetdemirag 🇨🇾 462 172 46ms 5 Feb 2025 379th dokutan 461 191 561ms 15 Jun 2024 380th MeWhenI 🇻🇦 461 299 44ms 3 Sep 2024 381st hacker112 🇸🇪 460 213 12ms 27 Jun 2024 382nd dokutan 447 172 21ms 27 Dec 2025 383rd msbranicky 445 349 6ms 14 Aug 2024 384th yuchuehw 442 180 20ms 4 Jun 2024 385th CaedenHarper 🇨🇦 439 309 426ms 21 Oct 2025 386th BREMAUCY 🇫🇷 428 186 25ms 4 Oct 2025 386th aksyristos 428 186 20ms 3 days ago 388th acollett89 424 231 31ms 18 Jul 2025 389th bac0id 424 317 566ms 24 Jun 2024 390th Yewzir 🇧🇪 423 188 14ms 10 Jun 2024 391st targrik 423 245 28ms 29 Jul 2025 392nd Babafaba 416 194 405ms 30 Oct 2025 393rd didion0 🇺🇸 415 236 20ms 21 Feb 2025 394th annaproxy 414 192 199ms 28 Aug 2025 395th MeWhenI 🇻🇦 414 293 1,517ms 20 Jun 2024 396th dokutan 406 334 500ms 5 Jun 2024 397th Babafaba 402 198 21ms 30 Oct 2025 398th coreynash 402 244 17ms 12 Jun 2024 399th Yewzir 🇧🇪 402 410 1,223ms 9 Jun 2024 400th Yewzir 🇧🇪 396 302 96ms 19 Dec 2024 First Prev 321–400 of 464 Next Last