Seven Boards of Skill

Seven boards of skill — qi qiao ban, 七巧板 — is the tangram: a square cut into seven flat pieces, and a silhouette to rebuild from them with the seams hidden. It has been played, almost unchanged, since the first Chinese puzzle books of 1813.

This is that puzzle, made endless.

EVERY FIGURE IS REAL
Nothing here is drawn and then hoped to be solvable. Each silhouette is built from a genuine arrangement of the pieces first, then shown to you with the joins erased — so every figure has a solution, and the game knows it. The geometry underneath is exact: pieces meet edge to edge with no rounding and no "almost." When it's right, it's exactly right.

FOUR WAYS TO PLAY
• Five Boards — five chunky pieces, no parallelogram, generous silhouettes. A way in.
• Seven Boards of Skill — the historical set, exactly as it was cut around 1800.
• The Extended Boards — nine to thirteen pieces from the older banquet-table sets the tangram descends from, with smooth outlines that give nothing away, and paradox pairs: two figures that look identical and aren't.
• Nightmare — the same figures with no help: no assisted snapping, no hints, a move budget and a clock.

Clear 6,000 figures in a tier and the next one opens. No tier ever ends.

HISTORY, NOT JUST PUZZLES
A curated set of classic figures sits alongside the endless supply, and the rules screen tells the real story — the banquet tables of 1194, the craze of 1813, the voyage to Philadelphia in 1816, Sam Loyd's beautiful hoax of 1903 — and the mathematics behind it: why every figure is exactly sixteen units, why only three angles ever occur, and why there are precisely thirteen convex shapes.

MADE TO BE HELD
Drag a tan from the tray. Tap to select it, turn it in steps of 45°, flip it over. Pieces click home when they're close, and the board celebrates when the figure is complete. Three frame styles, quiet sound cues you can switch off, and an optional daily reminder if you'd like a nudge.

HONEST BY DESIGN
Free. Works entirely offline. No ads, no account, no purchases, no tracking — the app doesn't even ask for internet access. Your progress lives on your phone and nowhere else.

Play one figure or six thousand. They don't run out.