Dominosa

Two squares. One small discovery.

Opening your local puzzle…

Tab-only play. Refreshing or closing loses this temporary session. It will never copy itself back to browser storage.

Choose a square, then an adjacent square.

Tap view · 44 px squares

Wider board? Scroll inside it ↔ ↕. Overview is read-only; tap targets never shrink.

Overview only. Return to tap view to make changes.

A place for every pair.

Every square is paired, and every number pair appears exactly once.

Number-pair checklist

Each pair is needed once. ✓ = placed once, ! = repeated. No warning does not guarantee a correct move.

300 fixed puzzles · local progress · no game account needed

From Simon Tatham’s Portable Puzzle Collection · MIT license & credits

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Find your next pair

Trivial and Basic are official generator settings, not human-calibrated difficulty. Board size is shown separately.

Puzzle group

Page

Browsing or going back keeps your current puzzle unchanged.

One of every pair.

Join two squares that share an edge to make a domino. Every square belongs to exactly one domino.
Use every unordered number pair from 0 to the board’s maximum once, including doubles. 0–2 and 2–0 are the same pair.
For example, a board using 0 and 1 needs three dominoes: 0–0, 0–1, and 1–1. Covering all squares with a repeated pair does not solve it.
Tap one square, then an adjacent square. A new pair replaces pairs touching either square, as one Undo action. Select the same pair again to remove it, or select one of its squares and choose Remove pair.

Keyboard: Tab into the board, arrow keys to move, Enter or Space to select. Escape cancels selection. Delete or Backspace removes the focused square’s pair. Focus is visible.

The last 128 edits are kept for Undo. Restart clears this attempt but keeps historical completion and your best result. “Best” is the fewest pair edits, counting removals and Undo, in a completed attempt. No timer is used.

Completion is checked again on the current board after every change. “Completed before” is history, not a claim that the current board is solved.

Progress is saved locally with IndexedDB when available. Saving failures are shown. Explicit tab-only play never reconnects or copies temporary progress back. Refresh/close can lose pending edits; browser warnings and crash durability are not guaranteed.