Marches & Gnats
Program a mechanical Turing machine to solve story-driven coding quests
Marches & Gnats is a puzzle game where every program is a Turing machine. Set in 19th-century Estonia, it has you write transition rules for the Logic Mill, a secret mechanical machine, to help a scholar from Dorpat. Each quest gives a problem and a minimal model of computation, and you iterate until your rules pass the hidden tests.
Free · Login needed · Browser · Intermediate
About Marches & Gnats
Quests run from unary addition and binary increment through sorting, Roman numerals, Sudoku validation, Vigenere ciphers, cellular automata and a player-versus-player Toads and Frogs. Leaderboards rank solutions by the number of head movements and by rule count, not by speed. It suits Advent of Code fans and anyone curious about computation from first principles.
It runs in the browser and is free, with a donation link. You can read every quest without an account, but submitting a solution needs one. The maker aims to add a quest every one to two weeks.
On Breakpoint since 31 Oct 2026.
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