What are the rules of the Domino Puzzle?
The board is cut into coloured regions, each with a rule, and the tray holds the dominoes to lay on it. Cover every square with one half of a domino. A number means the pips in that region add up to it; = means every square of the region shows the same pips; ≠ means no two show the same; <n and >n mean the total is less or more than n. A region with no rule takes anything.
Pick a domino in the tray (tap it again to flip it), then tap a square for its first half and a square beside it for the second. Tap a laid domino to take it back. On a keyboard, the arrows move on the board and Enter lays or takes back. Regions are outlined as well as coloured, so the rules never depend on telling colours apart.
| Level | Dominoes |
|---|---|
| Easy | 5 |
| Medium | 7 |
| Hard | 8 |
How do you solve a Domino Puzzle?
- Start with the tightest rules. A region of two squares that adds up to 12 can only be two 6s, and one that adds up to 0 can only be two blanks.
- Read the shape. A square with only one free neighbour shares its domino with that neighbour, which settles where one domino lies before you know which it is.
- Match = regions with the tray. Every domino here is different, so an = region that spans several dominoes needs dominoes sharing that number; often only one number appears often enough.
- Count the whole tray. The pips on the board add up to the pips in the tray, which can fix the total of a region with a loose rule or none.
How is your Domino Puzzle time calculated?
Your result is the time from Start until every domino is laid and every region keeps its rule. Beside it are the times you used Check, which marks any square showing the wrong pips, and Hint, which lays one domino where it belongs and lifts anything in its way. There is no rating, because no published typical time exists for puzzles built like these.
Does every Domino Puzzle here have exactly one answer?
Yes. The puzzles were made ahead of time, 3 levels of 30. Each board is dominoes laid side by side at random, all different, drawn from a double-six set of 28. The squares are then cut into regions, and each rule is read off that layout. A search tries every way to lay the tray, each domino both ways round; if more than one fits, the loosest rule is tightened, and the board is kept only when exactly one fits. The site's tests count every stored puzzle again.
Is this the same as Pips?
It uses the same kind of region rules as Pips, the domino puzzle The New York Times launched in August 2025. The puzzles and the page are this site's own, with no daily limit. If you like the adding up, try Kakuro, where each run of squares has a sum, or Calcudoku, where cages combine sums and products.