- ➊ Draw a single closed loop into the diagram.
- ➋ The sections of the loop run horizontally or vertically
between the center points of
orthogonally adjacent cells.
- ➌ The loop must pass through all white and gray cells but
must not cross a wall.
- ➍ In white cells the loop may turn by 90° but must not cross
- ➎ In gray cells (ice areas) the loop may cross itself, but
must not turn.