How to Play
Goal: Find all hidden domino boundaries in the number grid.
Tap-Tap: Tap a cell to select it, then tap an adjacent cell to pair them as a domino.
Swipe: On mobile, swipe from one cell to its neighbor to pair them.
Unpair: Tap a paired cell to remove the pairing.
Rule: Each domino (e.g. 2•5) appears exactly once. Duplicates are highlighted in red.
Tip: Start with pairs that can only go in one place. Use the reference panel below to track used dominoes.