How to play Overstamp: rules and the reverse-peeling strategy
Everything you need to play Overstamp, plus tips to get a better score.
How to play
- Recreate the picture of the day with as few stamps as possible.
- The small grid at the top is today's picture; the big board below is where you stamp. Striped cells are blank in the picture.
- Pick a stamp, rotate it if you like, and press it onto the board: it paints its cells in its ink, replacing whatever was there.
- Before you press, an outline shows where the stamp will land (move the mouse, slide your finger or use the arrow keys). A red ✗ means it can't go there.
- Stamps turn 90° at a time (↻, tap the chosen stamp again, or R) but never flip over, so an L and a J are different stamps.
- You can use every stamp as many times as you want.
- There are always more stamps than inks: every day at least one ink has two stamps with different shapes.
- Blank cells in the picture can never be inked: a stamp that would touch one can't be placed there.
- A stamp must fit entirely inside the board.
- Ink can't be wiped off: cover it with another stamp, undo the last stamp (↶) or start over (⟲).
- You win when your board matches the picture exactly. At par the game ends by itself; with more stamps a Finish button appears: hand it in, or undo and keep trying.
- Par is the fewest stamps possible. Match par for ⭐⭐⭐, par + 1 for ⭐⭐, anything more for ⭐.
- Undo and restart are free: only the stamps in your final picture count.
- The counter shows the stamps you've used against par. A small dot marks cells that already match the picture.
- The week gets harder: Monday and Tuesday 5×5 with 3 stamps, Wednesday to Friday 6×6 with 4, the weekend 7×7 with 5. Inks go from 2 on Monday to 4 from Friday, and par from 3 up to 9 on Sunday.
- Settings: colour-blind patterns (each ink gets its own stripes, dots, checks…; Automatic follows your system), highlight matching cells, stamp sound and vibration.
- Keyboard: arrows move the stamp, Enter stamps it, R turns it, Z undoes, 1 to 5 pick a stamp.
- Sharing shows your stars, how many stamps you used and the picture as coloured squares, never the solution. A friend's link shows the score to beat.
Strategy: think backwards
The top layer of the picture was stamped last. So instead of asking "what goes first?", ask "what could have been stamped last?" and work backwards. We call it reverse peeling.
Take this picture, with a red square stamp and a blue domino: 🟥🟥⬜ 🟥🟦⬜ ⬜🟦⬜
1. Find a spot where a stamp fits entirely on cells of its own ink. The blue domino fits the two blue cells, so it must have been stamped last. Peel it off: those cells become wildcards (✳️) that any earlier stamp could have covered. 🟥🟥⬜ 🟥✳️⬜ ⬜✳️⬜
2. Repeat. The red square now fits: three red cells plus a wildcard. Peel it and nothing coloured is left.
3. Read your peels in reverse: red square first, blue domino second. Two stamps, which is par.
More tips: start peeling from the smallest, most isolated colour patches; blank cells tell you where big stamps can't go; and if a shape can only fit one way on its own colour, that placement is almost certainly in the solution.