For grown-ups
FlatForge teaches the theorems of flat folding at a single vertex — Maekawa's (mountains minus valleys is two), Kawasaki–Justin's (alternate angles sum to 180°) and the big-little-big lemma — as proofs to name, not facts to memorise.
The last room hands the learner a confident assistant's answers, one of them wrong, to audit with a theorem. Whole crease patterns can still jam even when every vertex passes; deciding that in general is NP-hard, and the app says so plainly.
Text-forward, for older students: no cartoon cast. No timer, no score, no streak.
What it never does
- No accounts, no ads, no tracking — anything kept stays on this device.
- No streaks, timers to beat, points to chase or leaderboards.
- No chat, and nothing anyone types is sent anywhere.