The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 5 days. Why not try and solve them ahead of time?
Emirp Numbers 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 640th jared-hughes 774 85 1ms 30 Mar 2022 640th ovs-code 🇩🇪 774 85 2ms 21 Aug 2023 640th Steffan153 🇫🇮 774 85 2ms 21 Feb 2026 644th dokutan 774 92 123ms 14 Apr 2024 645th jacobly0 🇺🇸 774 124 1,757ms 22 Apr 2024 646th nstearns96 🇬🇧 772 70 16ms 6 Jan 2023 646th bizy-coder 772 70 11ms 17 Dec 2025 648th sisyphus-ppcg 🇦🇺 770 50 4ms 14 Jul 2022 649th MarcMush 🇫🇷 769 58 246ms 5 Jul 2021 650th DialFrost 🇸🇬 769 74 7ms 17 Aug 2025 651st bforte 769 86 118ms 26 Dec 2018 652nd xohmz 768 48 98ms 4 Nov 2018 652nd JRaspass 🇬🇧 768 48 91ms 29 Oct 2022 654th SirBogman 🇺🇸 767 52 37ms 3 Dec 2019 654th prplz 🇦🇺 767 52 34ms 3 Dec 2019 654th MeWhenI 🇻🇦 767 52 38ms 26 Oct 2021 657th MeWhenI 🇻🇦 767 72 144ms 17 Nov 2022 657th dokutan 767 72 163ms 11 Apr 2024 659th dokutan 767 109 7ms 23 Feb 2026 660th GrayJoKing 🇦🇺 765 86 1ms 12 Mar 2022 661st ovs-code 🇩🇪 762 69 167ms 17 Nov 2024 662nd Yewzir 🇧🇪 762 93 58ms 3 Aug 2023 663rd NewDefectus 🇮🇱 761 71 10ms 16 Dec 2021 663rd rschwa6308 🇺🇸 761 71 11ms 12 May 2023 663rd zbreit 🇺🇸 761 71 11ms 20 May 2023 663rd blaztoma 🇱🇹 761 71 10ms 10 Nov 2025 667th emgordon154 760 123 299ms 17 Jan 2025 668th ngn 🇧🇬 758 33 9ms 6 Feb 2022 669th detrumi 🇳🇱 758 94 133ms 26 Apr 2023 670th antimon2 🇯🇵 756 59 915ms 12 Sep 2022 671st Steffan153 🇫🇮 756 64 1,220ms 4 Jan 2023 671st Shanethegamer 🇺🇸 756 64 1,237ms 29 Mar 2023 673rd o0lit3 🇺🇸 754 51 5ms 12 Apr 2021 674th dokutan 754 94 65ms 14 Apr 2024 675th bbkr 753 49 100ms 14 Nov 2018 675th itiievskyi 🇺🇦 753 49 126ms 11 Aug 2020 677th anter69 🇭🇺 753 53 36ms 8 Feb 2023 677th fuzzylojik-golf 🇺🇸 753 53 37ms 6 Jul 2025 679th ffelixm 753 75 118ms 12 Jun 2025 680th sean-niemann 🇺🇸 752 105 21ms 19 Nov 2025 681st Lifesorder 751 72 10ms 12 Oct 2018 681st nwellnhof 🇩🇪 751 72 9ms 4 Feb 2021 681st annaproxy 751 72 10ms 28 Dec 2021 681st yzhs 🇩🇪 751 72 11ms 20 Jul 2022 681st fourth-bit 751 72 10ms 2 Jul 2023 686th scpchicken 🇵🇼 751 88 143ms 21 Feb 2023 687th ETHproductions 🇺🇸 750 75 31ms 21 Dec 2018 687th elisherer 🇮🇱 750 75 10ms 8 Apr 2019 687th emgordon154 750 75 10ms 13 Dec 2021 687th nwellnhof 🇩🇪 750 75 9ms 26 Jun 2023 691st emplv 🇱🇻 749 76 5ms 11 May 2021 691st sisyphus-ppcg 🇦🇺 749 76 5ms 14 Jul 2022 693rd HPWiz 🇳🇿 748 67 390ms 16 Jan 2024 694th GrayJoKing 🇦🇺 748 86 458ms 5 Mar 2022 694th fuzzylojik-golf 🇺🇸 748 86 460ms 30 Aug 2025 696th Irratix 🇳🇱 747 45 1ms 1 Nov 2020 696th GrayJoKing 🇦🇺 747 45 2ms 1 Nov 2020 696th primo-ppcg 🇹🇭 747 45 1ms 2 Nov 2020 696th KatieLG 🇬🇧 747 45 2ms 6 Dec 2020 696th sisyphus-ppcg 🇦🇺 747 45 1ms 11 Mar 2022 696th msbranicky 747 45 2ms 27 Jul 2023 696th adamnielson42 🇺🇸 747 45 2ms 8 Nov 2023 696th dokutan 747 45 2ms 11 Nov 2023 704th wiz0u 747 75 407ms 26 Jun 2023 704th pardouin 🇫🇷 747 75 402ms 8 Oct 2024 704th fuzzylojik-golf 🇺🇸 747 75 397ms 31 Aug 2025 704th amazingalek 🇳🇴 747 75 458ms 6 Jan 2026 708th Yewzir 🇧🇪 746 91 363ms 2 Oct 2025 709th JDiLenarda 🇫🇷 744 65 1,398ms 9 Oct 2020 710th DialFrost 🇸🇬 744 78 2ms 5 Nov 2023 711th dokutan 743 60 235ms 11 Apr 2024 712th dokutan 743 76 114ms 23 Jul 2025 713th laikoni 743 89 127ms 25 Dec 2018 714th Lydxn 🇨🇦 740 52 3ms 18 Jul 2022 714th xsot 🇸🇬 740 52 5ms 24 Jun 2025 716th xorraxrax 740 73 10ms 26 Oct 2019 716th btjones0 740 73 11ms 15 Jul 2022 716th Bmrl7 740 73 12ms 26 Feb 2024 716th firegene 🇮🇪 740 73 11ms 24 Feb 2026 720th rambox11 740 76 11ms 27 Apr 2018 First Prev 641–720 of 3,185 Next Last