- ➊ Draw a single closed loop into the diagram which does not visit a cell
more than once.
- ➋ The sections of the loop run horizontally and vertically
between the center points of
orthogonally adjacent cells.
- ➌ The loop must enter end exit each
region exactly once.
- ➍ The number in a region indicates how many cells of this
region are visited by the loop. In regions without a number the loop may
visit any number of cells.
- ➎ Cells not visited by the loop must not be orthogonally
adjacent across a region boundary.