This is one of my favorite puzzles. This is as additive as Sudoku.
1. The rectangle, divided by bold lines, is called "Room", Paint cells under the following rules.
2. Each number indicates how many painted cells in this room. While no number rooms may contain any number of painted cells.
3. White cells must not exceed two rooms in a straight line.
4. The painted cells must not be connected. White cells must not be separated by painted cells.