Dominosa

• Numbers
• Placement
• Regions

Pair all numbers into dominoes so every required domino appears exactly once.

1. Partition the grid into adjacent pairs of cells.
2. Each unordered number pair must be used exactly once as a domino.

• Track which domino pairs are already used: a locally valid placement may consume a unique combination.

Dominosa turns familiar domino tiles into a partitioning puzzle: determine where each tile begins and ends.

• Before making a move, check what each rule rules out and avoid blocking options you may need later.

• Where should I begin? Track which domino pairs are already used: a locally valid placement may consume a unique combination.
• What makes this game different? Each unordered number pair must be used exactly once as a domino.