Heyawake (from Japanese, -divided rooms-) is played on a rectangular grid. The grid is divided into rectangular -rooms-. Some rooms may contain a single number. These rooms must have the designated number of cells painted black. Other rooms may have zero or more cells painted black. - Black cells must t be orthogonally connected. - All white cells must be interconnected. - A line of connected white cells must t connect more than two rooms together.