- ➊ Blacken some cells of the diagram [paper] resp. color the
gray cells of the diagram black or white [interactively].
- ➋ Black cells must not be
- ➌ All cells with circles are white.
- ➍ Any path from one circled cell to an arbitrary other circle
cell must turn at least two times.
- ➎ All white cells must form a single
orthogonally contiguous area.