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 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 801st Creator-land 268 304 10ms 10 Jan 2024 802nd Weston49 268 358 10ms 20 Oct 2023 803rd MeWhenI 🇻🇦 264 414 14ms 1 May 2023 804th Zhenyu-Bo 260 314 10ms 31 Jul 2025 804th DrakeSeteraO 260 314 10ms 12 Nov 2025 806th dokutan 259 312 3ms 28 Jun 2025 807th lynn 259 315 9ms 14 Oct 2023 808th Bit125 258 316 10ms 31 Jan 2024 809th MeWhenI 🇻🇦 238 357 76ms 1 May 2023 810th dokutan 231 351 6ms 13 Aug 2024 811th MeWhenI 🇻🇦 224 302 34ms 1 May 2023 812th TerenceTux 219 443 2ms 22 May 2023 813th dokutan 218 450 377ms 16 Jul 2024 814th harperse 216 332 276ms 4 May 2023 815th MeWhenI 🇻🇦 216 607 5ms 1 May 2023 816th dokutan 212 337 251ms 4 Jul 2025 817th dokutan 208 202 43ms 17 Jun 2024 818th dokutan 208 505 120ms 28 Mar 2025 819th PYRiTEmonark 203 402 11ms 11 Sep 2023 820th kasarino 197 492 2ms 26 Feb 2026 821st dokutan 164 733 16ms 6 Jan 2025 822nd KatieLG 🇬🇧 154 981 322ms 15 Sep 2024 823rd AidanWalter 149 546 10ms 3 Jan 2025 824th muser-logiccpu 🇺🇦 141 576 11ms 25 Jul 2025 825th dokutan 140 972 704ms 23 Sep 2024 826th MeWhenI 🇻🇦 126 428 125ms 1 May 2023 827th dokutan 126 592 3ms 30 Dec 2023 828th holzay 117 699 10ms 6 Aug 2024 829th KatieLG 🇬🇧 101 743 280ms 15 Sep 2024 830th Msleizak 🇫🇷 98 727 311ms 22 Aug 2025 831st KatieLG 🇬🇧 96 1,014 87ms 15 Sep 2024 832nd BKGSr2 94 1,024 9ms 25 Sep 2023 833rd PierceZ 85 1,570 438ms 29 Nov 2023 834th alecdavidson 79 1,685 409ms 8 Dec 2023 835th KatieLG 🇬🇧 72 1,260 3ms 15 Sep 2024 836th MeWhenI 🇻🇦 40 4,114 2ms 1 May 2023 837th darrenks 🇺🇸 0 27 36ms 18 Apr 2025 838th plcc0 0 30 46ms 15 Feb 2026 839th Natanaelel 🇸🇪 0 37 53ms 27 May 2025 840th plcc0 0 45 731ms 23 Mar 2025 841st themoonisacheese 0 46 610ms 17 Mar 2025 842nd aditsu 0 48 101ms 12 Aug 2025 843rd ovs-code 🇩🇪 0 54 6ms 23 Sep 2025 844th namelessiw 0 56 178ms 21 Oct 2025 845th maweowo 🇩🇪 0 63 5ms 8 Oct 2025 845th AlephSquirrel 0 63 5ms 18 Dec 2025 847th ovs-code 🇩🇪 0 66 3ms 25 Jul 2025 848th ovs-code 🇩🇪 0 73 13ms 17 Jun 2025 849th KatieLG 🇬🇧 0 93 4ms 19 May 2025 850th dokutan 0 130 60ms 8 Feb 2026 851st edsrzf 🇳🇿 0 202 208ms 24 May 2025 852nd dokutan 0 212 9ms 11 Jan 2026 852nd Matter1024 🇮🇳 0 212 2ms 10 hours ago 854th dokutan 0 219 3ms 23 Sep 2025 First Prev 801–854 of 854