A little illumination
Light Up
Place bulbs using visibility and numbered clues.
THE OBJECTIVE
Think it through
Light every white square. Bulbs shine along rows and columns until a wall, and must not shine on one another. Numbers specify adjacent bulbs.
YOUR CONTROLS
Make your move
Click a square to place a bulb; right-click to mark a square that cannot contain one.
On a phone, use Touch: mark / reverse for a right-click action. Number puzzles include an on-screen number pad.
Choose an easier or harder grid in Type. Use Undo freely. Reveal solution shows the answer; it is a learning aid, not a hint. The timer starts on your first board interaction and stops automatically when you solve the puzzle. Use Finish practice to save an unfinished attempt. Complete 60 seconds of unrevealed practice with at least 3 board actions for the daily streak. Your last puzzle saves in this browser when device storage is available.
Puzzle engine by Simon Tatham and contributors · MIT licence · Full rules ↗