1. Pick a piece
Tap one of the seven shapes (I, O, T, S, Z, J, L). Press Rotate or the R key to turn it 90°.
Copy the Target picture onto your board with as few stamps as you can. Each stamp flips the cells it covers.
Tap one of the seven shapes (I, O, T, S, Z, J, L). Press Rotate or the R key to turn it 90°.
On a laptop, hover to see a blue preview, then click. On a phone, just tap a cell. The whole piece must fit inside the grid; a red preview means it does not.
A stamp flips every cell it covers. Empty cells become filled, and filled cells become empty again. This is the XOR rule.
Make your board exactly like the small Target. When Mismatch shows 0, you solved it. Press Check any time, then New Level for the next one.
Every stamp is one move. On Medium and Hard you have a move limit: when you reach it, you can’t stamp any more, so use Undo or Reset. Easy has no limit (∞).
Hints (H) paints the cells that are still wrong in coral. Show solution (S) draws the outline of each stamp used to build the target.
Each stamp flips covered cells (XOR). Overlap flips back. Rotate with R. Hints highlight mismatched cells (actionable).