Modus Ponens

A minimalist puzzle game of intuitionistic propositional logic. Each level is a map of rooms, and every room is a proposition. Proving a proposition lights its room: choose a closed room as your goal, then touch the rooms that prove it.

Implications are proved inside a hypothetical reality, where the premise is assumed. A fork splits a proof into two cases. Only intuitionistic logic: the excluded middle does not hold, and some rooms never open.

• Daily: one new puzzle every day, the same for everyone.
• Classic: puzzles one after another, at random or at a difficulty from 1 to 8.
• How to: a guided sequence that introduces one connective at a time.
• Trophies: every solved puzzle, with the formula you proved.