Daily Light Up

The rule

Light every white square, and never let one bulb shine on another.

A bulb lights its own square and every square it can see along its row and column, until a wall blocks the beam. Every white square has to end up lit.

No bulb may stand in another bulb's light. Two bulbs can share the squares they light, but they must never see each other.

A numbered wall says exactly how many bulbs touch it, counting only the four squares directly above, below, left and right. A nought is as useful as a four: it rules out all four neighbours at once.

Controls

Click a square to put a bulb there. Click again to mark it as empty, and once more to clear it. Shift click or right click goes round the other way. Lit squares turn yellow, and a pair of bulbs that can see each other turns red. Progress saves in this browser as you go, so you can come back to the same puzzle later today.