The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 6 days. Why not try and solve them ahead of time?
Reverse Polish 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 561st prplz 🇦🇺 706 165 2ms 14 Feb 2022 561st Szum123321 🇵🇱 706 165 2ms 29 Nov 2023 563rd CaedenHarper 🇨🇦 706 259 346ms 20 Nov 2025 564th edsrzf 🇳🇿 705 184 1,294ms 29 Apr 2025 565th AlephSquirrel 704 37 4ms 3 Aug 2023 566th GrayJoKing 🇦🇺 702 60 1,286ms 8 May 2022 567th Alex-x90 🇺🇸 702 166 2ms 8 Feb 2023 568th stefangimmillaro 701 57 38ms 18 Feb 2022 568th tatzyr 🇯🇵 701 57 39ms 26 Feb 2025 570th vgamula 🇺🇦 700 226 32ms 6 Nov 2023 571st JunkIce 699 95 403ms 3 Dec 2024 572nd Mandrzejy 🇵🇱 698 167 1ms 3 Nov 2024 573rd stefangimmillaro 698 193 3,008ms 12 Nov 2024 574th stefangimmillaro 698 262 301ms 5 May 2025 574th edsrzf 🇳🇿 698 262 300ms 10 Jun 2025 576th primo-ppcg 🇹🇭 696 48 1,032ms 15 Feb 2022 577th emgordon154 694 118 1,301ms 3 Dec 2024 578th Sp3000 🇦🇺 693 41 4ms 19 Jan 2024 578th MeWhenI 🇻🇦 693 41 5ms 2 Mar 2025 580th KingSkyrock 🇺🇸 692 106 13ms 17 Mar 2022 581st ian-h-chamberlain 🇺🇸 692 270 226ms 13 Nov 2025 582nd lifthrasiir 🇰🇷 691 50 3ms 28 Nov 2024 583rd KatieLG 🇬🇧 691 96 485ms 28 Oct 2024 584th Shanethegamer 🇺🇸 689 58 38ms 13 Feb 2022 584th SirBogman 🇺🇸 689 58 40ms 10 Jan 2024 586th Ripick 688 186 374ms 24 Jun 2025 587th edsrzf 🇳🇿 686 38 4ms 14 Oct 2025 587th error256 686 38 4ms 6 days ago 589th MathisBullinger 686 107 12ms 11 May 2022 589th CaedenHarper 🇨🇦 686 107 11ms 23 Aug 2025 591st iakolzin 684 205 61ms 1 Jul 2022 592nd nwellnhof 🇩🇪 683 110 335ms 24 May 2022 592nd AlephSquirrel 683 110 219ms 29 May 2023 592nd 5cw 🇺🇸 683 110 259ms 9 May 2024 592nd Seek64 🇩🇪 683 110 292ms 13 Sep 2024 596th kg583 🇺🇸 683 212 75ms 11 days ago 597th revlayle 🇺🇸 682 201 390ms 9 Dec 2022 598th CatsAreFluffy 681 206 70ms 24 Feb 2023 599th janbehrens 🇩🇪 678 199 505ms 26 Mar 2022 600th roavin 678 202 384ms 30 Jun 2022 601st shinh 677 59 40ms 21 Jun 2022 601st lacrosse 677 59 39ms 13 Dec 2025 603rd Mikey-Beep 🇬🇧 675 203 381ms 2 Sep 2024 603rd tomh1012 675 203 384ms 5 Sep 2025 605th 386asm 🇺🇸 675 222 43ms 5 May 2023 606th randolchance 673 109 13ms 4 Jan 2024 607th edsrzf 🇳🇿 673 124 5ms 6 Oct 2025 608th MeWhenI 🇻🇦 671 112 239ms 22 May 2024 609th MeWhenI 🇻🇦 670 146 6ms 13 Aug 2024 610th prestosilver 🇺🇸 670 174 1ms 18 Nov 2025 611th albanian-laundromat 668 39 4ms 13 Feb 2026 612th Natanaelel 🇸🇪 668 86 33ms 29 Jan 2024 613th janbehrens 🇩🇪 667 6 51ms 25 Nov 2022 614th snoozingnewt 🇨🇦 666 60 39ms 12 Feb 2026 615th Shanethegamer 🇺🇸 666 61 6ms 13 Feb 2022 616th alemelis 666 101 767ms 26 Aug 2024 617th xnor-gate 665 113 38ms 14 Feb 2022 618th Shanethegamer 🇺🇸 665 122 8ms 12 Apr 2024 619th janbehrens 🇩🇪 665 206 387ms 26 Feb 2022 620th Garklein 🇨🇦 664 52 3ms 13 Feb 2022 620th Natanaelel 🇸🇪 664 52 2ms 14 Jul 2023 620th SirBogman 🇺🇸 664 52 2ms 6 Nov 2023 623rd oeb25 663 282 219ms 16 May 2022 624th edsrzf 🇳🇿 662 182 113ms 30 Nov 2025 625th billings7 🇬🇧 662 207 389ms 16 Apr 2022 626th two-bad 🇬🇧 661 111 13ms 25 Feb 2024 626th Protothor 661 111 11ms 15 days ago 628th jmerle 🇳🇱 659 114 16ms 15 Feb 2023 629th jgbaldwinbrown 658 177 2ms 15 Jun 2022 630th IISResetMe 657 88 389ms 25 Dec 2025 631st m-tkach 🇺🇦 657 101 465ms 21 Jan 2024 632nd edsrzf 🇳🇿 657 282 6ms 20 Feb 2025 633rd rniii 655 61 41ms 15 Sep 2023 633rd olleicua 🇺🇸 655 61 38ms 6 Jan 2024 633rd anter69 🇭🇺 655 61 59ms 2 Apr 2024 633rd xsot 🇸🇬 655 61 40ms 23 Apr 2025 633rd beirigo 🇧🇷 655 61 37ms 17 Oct 2025 638th lynn 654 115 13ms 12 Feb 2022 638th Kacarott 🇦🇺 654 115 412ms 4 Feb 2025 640th CatsAreFluffy 654 178 2ms 24 Feb 2023 First Prev 561–640 of 1,185 Next Last