Draw a single closed loop that visits every cell exactly once, travelling horizontally or vertically, and that never crosses or touches itself. In the cells with a white circle the path goes straitght, and in the cells with a black circle the path must take a 90 degree turn.
MOUSE: Click between two cells to draw a connecting line. Click again to mark that there can't be a line. A third click will eliminate any symbol.
The button above will work only during the competition!