Solving constraint satisfaction problems III: Paint by numbers
We can generalize the technique of interacting copies to write a single procedure to handle a whole class of puzzles. These puzzles are known as Paint-by-Numbers, and also as Nonograms, or O-e-kaki in Japanese. We are given a rectangular grid of pixels. For each row and column, we are told the lengths of the groups of pixels that are black in that row or column. The challenge is to use that information to figure put the exact placement of the pixels.
