Dominosa Domino Logic
Dominosa Domino Logic hands you a rectangle of numbers and one rule: carve it into dominoes so that every possible pair of values shows up once and only once. It is a quiet, pencil-style puzzle that rewards careful reading of the grid.
Simon Tatham wrote it for his Portable Puzzle Collection. It loads in your browser with nothing to install, and each new grid is generated with a single solution at the level you choose.
How to play Dominosa Domino Logic
The default set uses the numbers 0 to 6, which makes 28 dominoes on a grid eight wide and seven tall. Every domino covers two neighboring numbers, side by side or one above the other. A full set has exactly one 0-0, one 0-1 and so on up to one 6-6.
Click between two numbers to lay a domino over them, and click it again to lift it off. If you place the same pair twice, both copies turn red. Right-click between two numbers to draw a short line meaning no domino goes here.
The puzzle is solved when the whole grid is covered and every domino in the set has been used once. Bigger and smaller sets, plus Trivial, Basic, Hard and Extreme logic levels, are in the Type menu.
Controls
| Action | Keyboard | Mouse | Touch |
|---|---|---|---|
| Place or remove a domino | Arrow keys between two numbers, then Enter | Left-click between two numbers | Tap between two numbers |
| Mark no domino here | Space | Right-click between two numbers | Press and hold |
| Highlight a number | Type the number | Right-click the number | Press and hold the number |
| Undo, redo, new puzzle | U, R, N | — | — |
Tips
- Hunt for pairs that occur only once in the whole grid. If a 2 sits beside a 5 in only one spot on the board, the 2-5 domino has to go right there.
- A number in a corner has only two neighbors. If one of those pairings is already used, the other is forced.
- Every time you place a domino, cross out other places where the same pair appears. Those lines often force new dominoes nearby.
- Highlight a number to see all of its copies at once. It makes it far easier to spot which pairings are still available.
- Watch for cells that have only one open neighbor left. A lonely cell must join that neighbor.
If you like Dominosa Domino Logic, try these
Magnet DominoesPlacement logic with dominoes again, this time choosing which pieces are magnets and which way their poles face.
DominoesTry the real tiles instead: match pips end to end with a double-six set and empty your hand first.
Questions
How do you solve Dominosa Domino Logic without guessing?
Look for pairs that can only fit in one place and for cells with just one free neighbor. Placing those forced dominoes rules out other spots, and the chain usually carries you through.
Why are some of my dominoes red?
Red means a pair is on the board twice. A full set contains each pair once, so one of the copies has to move.
Can I play Dominosa Domino Logic on a phone?
Yes. Tap between numbers to place dominoes, and press and hold to draw the no-domino lines or highlight a number.
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