How to play
Dark walls block light; a numbered wall wants exactly that many bulbs in the four squares touching it, and a 0 wants none — usually the best opening move on the board. Pick Bulb and tap to place one: it lights its own square and shines left, right, up and down until a wall or the edge stops it. No bulb crosses a square off; that is your own note and changes nothing about the board.
You are finished when every open square is lit and no two bulbs can see each other along a row or column. The crosses do not have to be filled in — the bulbs decide it. Check names any rule your bulbs already break, and never says more than that.