Follow the story. Try a proof. Let curiosity choose how deep you go.
Walk in through the manga: seventeen chapters, sixty-four pocket pebbles, zero required formulas. The Lean source stays behind glass until you ask for it.
Straight to the mathematicsBegin at the proof map — thousands of named theorems — then climb the full ladder from clock inverses to R = T. The story keeps telling itself beside you; it will keep you honest.
Made for company: one reader who loves math and one who does not — one sofa. Whatever each of you finds carries over to the tea salon.
Seventeen chapters, one extraordinary argument. One small discovery is enough for today.
Pip’s rule: mistakes are clues. Every chapter is open, and every question allows another try.
Search the local catalogue in English or Japanese. Major landmarks have Japanese titles. Open the full original proof on GitHub for the complete context.
Short scenes. Real logical goals. A pigeon who is very invested in your success.
theorem one_door (P Q : Prop) (key : Q) : P ∨ Q := by sorry
The story and source are readable here. Enable JavaScript to edit proofs, try quizzes, and explore the interactive map.
These are invented practice attempts, checked here when you try them. They are not the history of the FLT proof.
“I picked the left door. Could the Q key please reconsider its type?”
left
exact keyleft chose the P branch, but key proves Q. Restart the choice with right, then provide key. An Or proof needs one matching branch.
right exact key
Opening the casebook…
One door is enough
Start with the cake-scale story. You only need to read one small piece at a time. If you are in the Fermat story, start with Story depth, then the words listed before the chapter.
You do not need to know Lean, symbols or university mathematics to begin. Definitions come first in the small stories.
Look at the small example before the general formula. Ask what changed and what stayed the same.
Close this panel to return to the exact place you were reading. These are prepared hints for this page.
Start with the first small story →