The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 4 days. Why not try and solve them ahead of time?
Forsyth–Edwards Notation in all languages in bytes. 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 Bytes Time Submitted 640th tomh1012 579 183 469ms a min ago 642nd retrohun 577 144 2ms 27 May 2023 643rd aksyristos 577 198 9ms 10 days ago 644th snoozingnewt 🇨🇦 576 145 1,515ms 31 Oct 2025 645th celiendonze 🇨🇭 572 200 10ms 3 May 2023 646th Yewzir 🇧🇪 572 245 3ms 18 Jan 2024 647th PhysicDev 🇫🇷 569 201 10ms 25 May 2023 648th MeWhenI 🇻🇦 569 214 3ms 1 May 2023 649th MeWhenI 🇻🇦 565 229 40ms 26 Aug 2023 650th weliveinhell 🇭🇹 564 198 11ms 25 Sep 2023 651st Wildst 563 203 10ms 7 Jul 2023 652nd Yewzir 🇧🇪 559 237 10ms 4 Apr 2024 653rd acollett89 558 200 9ms 8 Aug 2025 654th AbuzarN 558 205 17ms 22 Nov 2023 655th KrausRaus 🇺🇸 557 239 2ms 11 Oct 2023 656th msbranicky 554 231 1ms 28 Sep 2023 657th emgordon154 552 124 35ms 26 Jul 2024 658th dokutan 552 254 3ms 5 Feb 2025 659th Babafaba 547 177 497ms 25 Oct 2025 660th MeWhenI 🇻🇦 546 287 46ms 3 Jul 2023 661st madex 🇩🇪 544 185 1ms 23 Jul 2025 662nd ellis-rix 542 211 11ms 11 May 2023 662nd RaBa21 🇭🇺 542 211 10ms 19 Jul 2025 664th yzhs 🇩🇪 540 245 129ms 25 Jun 2023 665th Kloppermand 🇩🇰 539 212 10ms 26 May 2023 665th mdnestor 539 212 10ms 27 May 2024 667th MeWhenI 🇻🇦 539 296 34ms 6 Jun 2023 668th KatieLG-Transpiler 🇬🇧 538 180 526ms 16 Aug 2024 669th Yewzir 🇧🇪 538 229 11ms 30 Dec 2024 670th The-Wolfson 538 312 144ms 9 Feb 2025 671st dokutan 537 227 3ms 29 Apr 2025 672nd Mabeloid 🇳🇴 535 188 2ms 2 Oct 2024 673rd adoxography 534 128 34ms 22 May 2023 674th Mikey-Beep 🇬🇧 532 215 16ms 28 Aug 2023 675th lelbal 529 216 10ms 17 Oct 2024 675th yjgnaw 529 216 10ms 24 Jul 2025 677th Yewzir 🇧🇪 526 184 555ms 4 Feb 2024 678th mrmena 🇦🇺 524 213 11ms 29 Mar 2024 679th te-chnical 522 219 10ms 19 Feb 2026 680th JunkIce 521 186 526ms 24 Jan 2025 681st KatieLG 🇬🇧 521 311 2ms 1 May 2023 682nd logalex8369 🇺🇸 517 216 13ms 18 Dec 2025 683rd kzheng808 517 221 9ms 14 Jun 2023 683rd elgan65536 🇺🇸 517 221 9ms 9 Nov 2024 685th MeWhenI 🇻🇦 517 528 12ms 28 Aug 2023 686th daniel-cardone 515 217 9ms 8 Sep 2023 687th Masttest 515 222 9ms 31 Jan 2024 687th yokasuretsu 515 222 10ms 14 Jan 2025 689th msbranicky 514 259 2ms 11 Oct 2023 690th msbranicky 512 202 88ms 18 Aug 2023 691st jerrandolph 512 312 294ms 2 Nov 2023 692nd amazingalek 🇳🇴 511 207 431ms 11 Jan 2026 693rd MeWhenI 🇻🇦 510 163 2ms 1 May 2023 694th DrPrettyman 508 225 10ms 25 May 2023 694th mrmena 🇦🇺 508 225 10ms 29 Mar 2024 696th TheZwierzLF 🇵🇱 507 191 503ms 22 Nov 2025 697th m42km 506 226 10ms 3 Feb 2024 698th ridingqwerty 🇺🇸 504 227 10ms 30 Jan 2024 698th Andrey2001 504 227 10ms 1 Feb 2026 698th tomh1012 504 227 16ms 24 days ago 701st klixel 🇨🇦 503 345 184ms 23 Jul 2025 702nd FortuiteMan 🇫🇷 501 228 16ms 11 Jul 2025 703rd msbranicky 497 174 169ms 9 Jan 2025 704th galloj 🇨🇿 497 230 14ms 8 May 2023 705th jameswmccarty 495 231 10ms 6 Apr 2025 706th Yewzir 🇧🇪 493 245 2,889ms 9 Feb 2024 707th Schmitt-Very-Cool 493 275 523ms 26 Sep 2025 708th Natanaelel 🇸🇪 492 269 126ms 5 May 2023 709th prplz 🇦🇺 484 208 1ms 9 May 2023 710th keelimeguy 🇺🇸 484 236 29ms 6 May 2025 711th ItsMeNoobieboy 480 238 10ms 6 May 2023 712th dokutan 479 244 211ms 29 Jun 2024 713th madex 🇩🇪 479 362 252ms 20 Jul 2025 714th dokutan 478 143 39ms 21 Apr 2025 715th msbranicky 473 217 2,856ms 9 Jan 2025 716th HenryTy83 473 236 10ms 3 May 2023 717th Yewzir 🇧🇪 472 213 2ms 9 Feb 2024 718th janbehrens 🇩🇪 471 208 40ms 1 May 2023 719th madex 🇩🇪 469 146 33ms 20 Jul 2025 720th IISResetMe 465 164 348ms 3 Jan 2026 First Prev 641–720 of 856 Next Last