Light Up

Place light bulbs on the white cells. A bulb lights its own cell and shines along its row and column until it hits a black wall or the edge of the board.

• Every white cell must be lit.
• No two bulbs may shine on each other.
• A black wall with a number must have exactly that many bulbs directly next to it (up, down, left, right). Walls without numbers can have any amount.

Controls

• Tap a white cell to cycle: empty → 💡 bulb → • dot (no bulb here) → empty.
• Right-click or long-press toggles a dot. Drag to paint dots.
• Keyboard: arrows move, Space cycles, X toggles a dot, Ctrl+Z undoes.

Bulbs that see each other and walls with too many bulbs turn red; satisfied walls turn green. Check highlights mistakes, Hint fixes one cell. Each puzzle has exactly one solution.

Tips

Start with 4s (all four sides get bulbs), 0s (no bulbs around) and 3s in corners. A cell that can only be lit by one remaining spot forces a bulb there.