Author: Andrey Bogdanov
Shade some cells black to create a path - a chain of blackened squares which doesn't touch itself even in a point. Begin and end of the path are shown. Path should pass through all cells with digits. Path can't make turn in a cle with a digit and the digit shows the length of the corresponding straight segment of the path.
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.