Author: Andrey Bogdanov
Shade some cells so that digits in cells show how many cells must be shaded around the cell with the digit, including the cell itself.
Grid control: Click the mouse button at the selected cell to change the color of the cell. Second click will put auxiliary circle, 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.