- Blacken some cells of the grid [on paper] or color the
gray cells of the grid either black or white [interactively].
- Cells with numbers are always white. The numbers indicate
how many of the
orthogonally and diagonally adjacent cells are black: Each number
indicates a group of orthogonally adjacent black cells; different groups are
separated by at least one white cell. Position and sequence of the clue
numbers is irrelevant.
- A question mark indicates "any number" greater than zero.
- All black cells must form an
orthogonally-connected area.
- The black cells must not cover an area of 2x2 cells or
larger.
Knapp daneben: All given numbers are wrong. The correct number is either 1
higher or 1 lower, meaning a 1 can possibly turn into a zero.