To solve a GOKIGEN puzzle you must insert a diagonal line into every cell of the puzzle. The numbers at the corners of some of
the cells indicates the number of diagonals which converge on that point. The diagonal lines must not combine to form a loop of any size.
Solving the puzzle is a purely mouse operation. If you click the mouse when the mouse cursor is within a cell, a diagonal will be
placed in the cell, and that diagonal will pass through the cell corner which is nearest to the mouse cursor. If you make a mistake, a second click in
approximately the same location will remove the diagonal.