Context

Context is a rectangular or square grid with numbers in some cells. The aim is to blacken cells of a grid according to the following rules:

• All the white cells must be connected horizontally or vertically.
• A cell with a number can be blacken. Two black cells must not be orthogonally adjacent.
• The number in a white cell indicates the number of orthogonally adjacent black cells.
• The number in a black cell indicates the number of diagonally adjacent black cells.

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