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?
Leap Years 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 636th AutumnWind75 900 79 446ms 10 Dec 2025 636th bac0id 900 79 110ms 27 Jan 2026 643rd retrohun 899 46 1ms 16 Jun 2024 644th sean-niemann 🇺🇸 898 38 79ms 14 Sep 2023 644th blaztoma 🇱🇹 898 38 75ms 2 Nov 2025 646th MeWhenI 🇻🇦 897 54 111ms 15 Oct 2022 646th Yax42 🇫🇷 897 54 104ms 5 Oct 2025 648th AlephSquirrel 897 60 5ms 13 Mar 2023 648th Lydxn 🇨🇦 897 60 15ms 31 Jan 2025 648th edsrzf 🇳🇿 897 60 14ms 14 Dec 2025 651st Attero 🇸🇪 896 61 374ms 21 Nov 2021 651st nwellnhof 🇩🇪 896 61 387ms 21 Nov 2021 651st tomtheisen 🇺🇸 896 61 411ms 21 Nov 2021 651st MeWhenI 🇻🇦 896 61 356ms 10 Oct 2022 651st DialFrost 🇸🇬 896 61 420ms 8 Nov 2023 651st namelessiw 896 61 351ms 11 Jul 2024 651st dokutan 896 61 420ms 25 Sep 2024 651st pardouin 🇫🇷 896 61 394ms 26 Sep 2024 651st b-illy 🇬🇧 896 61 387ms 21 Jan 2025 651st fuzzylojik-golf 🇺🇸 896 61 429ms 28 Jun 2025 651st edsrzf 🇳🇿 896 61 397ms 21 Dec 2025 662nd ovs-code 🇩🇪 895 89 6ms 8 Jul 2024 663rd Shanethegamer 🇺🇸 894 60 115ms 15 Apr 2025 663rd snoozingnewt 🇨🇦 894 60 111ms 1 Dec 2025 663rd DialFrost 🇸🇬 894 60 102ms 1 Dec 2025 663rd emgordon154 894 60 101ms 3 Dec 2025 663rd sean-niemann 🇺🇸 894 60 103ms 4 Jan 2026 663rd Steffan153 🇫🇮 894 60 119ms 27 Feb 2026 669th canissimia 🇦🇶 893 83 6ms 1 Aug 2023 670th DialFrost 🇸🇬 892 36 3ms 11 Aug 2024 670th MeWhenI 🇻🇦 892 36 3ms 12 Aug 2024 670th sean-niemann 🇺🇸 892 36 3ms 13 Aug 2024 670th GrayJoKing 🇦🇺 892 36 3ms 26 Aug 2024 670th lynn 892 36 3ms 21 Dec 2024 675th dokutan 892 43 132ms 28 Sep 2024 675th emplv 🇱🇻 892 43 127ms 29 Oct 2024 677th primo-ppcg 🇹🇭 891 36 33ms 8 Dec 2018 677th nwellnhof 🇩🇪 891 36 37ms 28 Apr 2020 677th Waffle3z 891 36 35ms 14 Jul 2021 677th lynn 891 36 36ms 10 Sep 2021 677th sean-niemann 🇺🇸 891 36 35ms 5 Apr 2022 677th jared-hughes 891 36 35ms 9 Sep 2022 677th MeWhenI 🇻🇦 891 36 33ms 10 Oct 2022 677th ovs-code 🇩🇪 891 36 34ms 9 May 2023 677th DialFrost 🇸🇬 891 36 35ms 8 Nov 2023 677th pardouin 🇫🇷 891 36 35ms 21 Aug 2024 677th dokutan 891 36 35ms 25 Sep 2024 677th FlyingPenguin223 891 36 38ms 17 Dec 2024 677th fuzzylojik-golf 🇺🇸 891 36 36ms 25 Aug 2025 690th rambox11 891 44 9ms 20 Dec 2018 690th skps2010 891 44 10ms 4 Jan 2019 690th obarakon 891 44 10ms 9 Jan 2019 690th elisherer 🇮🇱 891 44 10ms 28 Mar 2019 690th goldenice 891 44 10ms 4 Apr 2019 690th user189032 891 44 9ms 29 May 2019 690th marcin7Cd 891 44 10ms 13 Mar 2020 690th ondras 891 44 9ms 3 May 2020 690th daisy-lau 891 44 11ms 20 May 2020 690th efgen 891 44 10ms 12 Jun 2020 690th itsh01 891 44 9ms 15 Jul 2020 690th thisishowmymindworks 🇳🇴 891 44 9ms 20 Jul 2020 690th ToriTheChicken 891 44 9ms 21 Jul 2020 690th ehouais 891 44 9ms 23 Aug 2020 690th Athe81 891 44 10ms 30 Oct 2020 690th jn-lp 🇺🇦 891 44 10ms 1 Nov 2020 690th pandapawskat 891 44 10ms 3 Dec 2020 690th boxjelly 891 44 13ms 14 Feb 2021 690th blader0x 891 44 10ms 28 Mar 2021 690th heypwesto 🇳🇿 891 44 10ms 20 Apr 2021 690th Shanethegamer 🇺🇸 891 44 13ms 22 May 2021 690th Natanaelel 🇸🇪 891 44 9ms 1 Oct 2021 690th alex-oser 🇲🇰 891 44 9ms 5 Oct 2021 690th igmcdowell 891 44 11ms 25 Nov 2021 690th shellbertt 🇨🇦 891 44 10ms 3 Dec 2021 690th ZakkkkAttackkkk 🇵🇭 891 44 11ms 17 Dec 2021 690th fitzdotlol 🇺🇸 891 44 10ms 8 Mar 2022 690th vincens2005 🇺🇸 891 44 9ms 30 Mar 2022 690th otubby 891 44 10ms 30 Mar 2022 690th NathanGabrielson 891 44 9ms 30 Mar 2022 690th inverseLorentz 🇦🇺 891 44 10ms 28 Jun 2022 First Prev 641–720 of 4,855 Next Last