Scrin Puzzle: 250 Hard Logic Brain Puzzles
Scrin (“Screen”) is a logic puzzle published by Nikoli. A rectangular or square grid contains circles (empty or with numbers) in some cells. The goal is to divide the grid into rectangular regions. Each region contains not more than one circle. The grid may contain regions without circles. A region must have the same number of cells as a number in a circle. Regions must not share an edge. Regions must form a single non-branching loop where all of them touch each other by corners.