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 cell 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. 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.