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?
Collatz 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 641st GrayJoKing 🇦🇺 876 84 35ms 19 Jun 2022 641st primo-ppcg 🇹🇭 876 84 36ms 29 Jun 2022 641st MeWhenI 🇻🇦 876 84 38ms 30 Dec 2025 644th Shanethegamer 🇺🇸 875 51 472ms 15 May 2023 645th c0d3-4-F00d 🇩🇪 874 61 16ms 6 May 2022 645th jackkav 874 61 11ms 26 Jun 2022 645th TechNolaByte 874 61 12ms 6 Jul 2022 645th Heathcorp 🇦🇺 874 61 12ms 17 Jul 2022 645th C0de5mith 🇺🇸 874 61 14ms 3 Aug 2022 645th sebipopa 🇷🇴 874 61 11ms 18 Aug 2022 645th moikaturns 🇬🇧 874 61 10ms 25 Sep 2022 645th FlorianCassayre 🇫🇷 874 61 14ms 27 Sep 2022 645th Mazn3k 874 61 11ms 1 Feb 2023 645th tvcv901 874 61 11ms 22 Mar 2023 645th unfinishedprogram 874 61 12ms 19 Jul 2023 645th snoozingnewt 🇨🇦 874 61 11ms 23 Sep 2023 645th funnyboy-roks 874 61 11ms 9 May 2024 645th bac0id 874 61 11ms 29 Jun 2024 645th FortuiteMan 🇫🇷 874 61 11ms 10 Oct 2024 645th RobertHoeh 874 61 15ms 5 Apr 2025 645th LvLError 874 61 11ms 29 May 2025 645th miles-evan 874 61 11ms 5 Aug 2025 645th alexsave 874 61 11ms 13 Oct 2025 664th NerdyMcNerd42 874 64 20ms 26 Oct 2022 664th tpasfieldERAU 874 64 23ms 14 Nov 2022 664th CheeseCake628 🇳🇴 874 64 23ms 6 Jan 2023 664th adamnielson42 🇺🇸 874 64 19ms 25 Apr 2023 664th nathsou 🇫🇷 874 64 21ms 2 Sep 2023 664th zwxzwxzwx21 874 64 24ms 30 Jan 2024 664th steffan-polygolf 874 64 21ms 8 Mar 2024 664th Jacob385 874 64 59ms 4 Apr 2024 664th gallium-gonzollium 874 64 28ms 26 Aug 2024 673rd dokutan 873 62 5ms 28 Apr 2025 674th Shanethegamer 🇺🇸 873 66 172ms 4 May 2022 674th scpchicken 🇵🇼 873 66 254ms 5 May 2022 674th sisyphus-ppcg 🇦🇺 873 66 173ms 6 May 2022 674th Natanaelel 🇸🇪 873 66 144ms 15 Jun 2022 674th Z-snails 873 66 254ms 27 Feb 2023 674th Jeremy-Stafford 873 66 258ms 27 Feb 2023 674th alomiF 873 66 293ms 1 Sep 2023 674th btnlq 873 66 145ms 17 Oct 2023 674th Shengxuan-Zhang 873 66 278ms 20 Feb 2026 683rd johnnythedoggie 873 72 96ms 13 May 2022 683rd kaascevich 873 72 96ms 8 Jul 2025 683rd madeforlosers 873 72 102ms 10 days ago 686th DialFrost 🇸🇬 873 73 149ms 3 Jun 2025 687th c0d3-4-F00d 🇩🇪 873 89 364ms 5 May 2022 687th fkantelberg 873 89 374ms 15 Jul 2023 687th bac0id 873 89 354ms 26 Sep 2023 687th TRexOnGit 873 89 364ms 16 Feb 2024 691st inventshah 873 97 61ms 6 May 2022 691st roupiq 🇵🇱 873 97 60ms 22 Nov 2023 691st emgordon154 873 97 59ms 8 Feb 2026 694th HPWiz 🇳🇿 872 49 265ms 4 May 2022 694th JayXon 🇺🇸 872 49 250ms 5 May 2022 694th Steffan153 🇫🇮 872 49 256ms 10 Dec 2022 694th ovs-code 🇩🇪 872 49 403ms 24 Oct 2023 694th sean-niemann 🇺🇸 872 49 268ms 12 Jul 2024 699th DialFrost 🇸🇬 872 76 82ms 17 Mar 2025 700th DialFrost 🇸🇬 872 86 40ms 24 Oct 2024 700th stefangimmillaro 872 86 39ms 14 Jan 2025 702nd janbehrens 🇩🇪 872 90 467ms 21 Apr 2023 702nd Yewzir 🇧🇪 872 90 459ms 22 Apr 2023 702nd Ripick 872 90 459ms 27 Nov 2024 702nd emgordon154 872 90 476ms 10 Dec 2025 706th MeWhenI 🇻🇦 872 109 286ms 9 Feb 2023 707th GolfingSuccess 🇬🇷 870 71 2ms 5 May 2022 707th emplv 🇱🇻 870 71 2ms 5 May 2022 707th JayXon 🇺🇸 870 71 2ms 7 May 2022 707th m-tkach 🇺🇦 870 71 2ms 15 May 2022 707th nwellnhof 🇩🇪 870 71 2ms 5 Jun 2022 707th Irratix 🇳🇱 870 71 2ms 13 Jun 2022 707th michael-pruglo 🇺🇦 870 71 2ms 13 Jul 2022 707th stefangimmillaro 870 71 2ms 2 Jun 2023 707th kkoenig 870 71 2ms 21 Dec 2023 707th JohandeRuiter 🇳🇱 870 71 2ms 14 Sep 2024 707th masinag 🇮🇹 870 71 2ms 6 Oct 2024 718th AlephSquirrel 870 80 12ms 20 Apr 2023 718th ashtraypettingzoo 🇺🇸 870 80 14ms 1 Apr 2024 720th CaedenHarper 🇨🇦 869 54 1,451ms 27 Sep 2025 First Prev 641–720 of 3,621 Next Last