- ➊ Blacken some cells of the diagram [paper] resp. color the
gray cells of the diagram black or white [interactively].
- ➋ A cell with a number cannot be blackened. The number
indicates how many white cells can be seen altogether looking north, south,
east and west (including the cell with the number) up to a black cell or the
edge of the diagram.
- ➌ Black cells must not be
- ➍ All white cells must form a single
orthogonally contiguous area.