2. The grid shown is divided into rectangular "rooms". Some rooms have numbers in their corners; these numbers indicate how many black cells that room contains. An unnumbered room may contain any number of black cells in it.
3. The white cells may not span more than two consecutive rooms in an uninterrupted horizontal or vertical line.
4. No two black cells may share an edge. All of the white cells must be connected to each other through their edges.
