- Place light bulbs in some of the white cells so that all
white cells are lit and no light bulb is lit by an other light bulb.<
- A light bulb shines horizontally and vertically up to the
next black cell or the edge of the grid.
- A number in a black cell indicates how many light bulbs
must be placed in
orthogonally adjacent cells.
Additional Rules:
Every light bulb must light exactly one other light bulb.