Divide the grid, along its lines, into regions. Regions of the same size cannot share an edge, and each given digit must be in a region of that size. Regions may not have any given digits in them, or may have more than one.
Divide the grid, along its lines, into regions. Regions of the same size cannot share an edge, and each given digit must be in a region of that size. Regions may not have any given digits in them, or may have more than one.