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Norinori

Norinori is a logic puzzle invented by Nikoli. A rectangular or square grid is divided into regions. The aim is to blacken some cells of a grid according to the following rules:

• Every region contains exactly two black cells.
• Each black cell must be a part of a 2 x 1 or 1 x 2 block (domino), irrespective of the region borders.
• No two dominoes may share an edge. Black blocks can touch each other diagonally.

Cross+A can solve puzzles from 3 x 3 to 30 x 30.