Author: Andrey Bogdanov
Shade some cells in the grid so that all shade cells are connected. Numbers inside outlined areas indicate the number of shaded cells in that area. There may not exists a run of four or consecutive shaded or unshaded cells horizontally or vertically anywhere in the grid.
Grid control: Click the mouse button at the selected cell to change the color of the cell. Second click will put auxiliary cross sign, which doesn't affect correctness of the solution, but helps visually. You can also drag the content of one cell to another with the mouse. More details about grid control are at the help page.