Chocona ("Chocolate") consists of a rectangular or square grid divided into regions. The aim is to blacken some cells of a grid according to the following rules:
- A cell with a number indicates how many cells in the region must be blackened.
- In a region without a number any number of cells may be blackened.
- The black cells must form rectangles, independently of the region borders.
- The black rectangles must not be orthogonally adjacent.
Cross+A can solve puzzles from 3 x 3 to 30 x 30.