Light and Shadow is a binary determination puzzle in which the cells in a grid are split into shaded and unshaded cells.
The objective is to divide the grid into shaded and unshaded cells, subject to the following rules:
- Each region contains one number with an area equal to that number.
- Numbers in white cells are part of white regions; numbers in gray cells are part of gray regions.
- Same colored regions cannot share an edge.
A standard 10x10 light and shadow and its solution.