Author: Andrey Bogdanov
Shade some empty cells black to create a single connected wall. No 2x2 square can be completely shaded. Cells with numbers can't be shaded. All unshaded cells form islands. Each island contains exactly one numbered cell which equals the size of the island.
Grid control: Click the mouse button at the selected cell to change the color of the cell. More details about grid control are at the help page.