A grid logic puzzle where you place bulbs to light every white cell without letting any two bulbs shine on each other.
Light Up Lamp Puzzle hands you a floor plan made of white and black cells and asks you to light every room. Each bulb you drop on a white cell sends light along its row and column. The black squares act as walls, and some of them show a number.
It is a calm logic game with clear rules and no luck involved. As you work, lit squares turn yellow, so you can watch the dark patches shrink with every bulb you add.
The goal
You finish a board when three things are true at the same time:
- Every white square is lit, either by a bulb on it or by a beam passing through it.
- No bulb sits in another bulb’s light. Two bulbs may never see each other along an unblocked row or column.
- Each numbered wall touches exactly that many bulbs on its four sides. Diagonal squares do not count.
A bulb’s beam travels in straight lines until a wall or the border stops it. It never turns a corner. Walls without a number only block light, and any number of bulbs can sit next to them. When the last condition falls into place, the board flashes.
Reading the clues
The game warns you about trouble in red. A bulb goes red when it is caught in someone else’s beam. A numbered wall goes red if it already has too many neighbors with bulbs, or if there is too little free room left beside it to ever reach its count.
Marks are your other tool. Right-click a square, press Space or I, or hold your finger on it to show that it cannot take a bulb. Marked squares are a note to yourself and help you see where the remaining light must come from.
Winning moves
Big numbers give the most away. A 4 has to be surrounded by bulbs, and a 3 pressed against the edge of the grid has only three open sides, so all of them get a bulb. A 0 does the opposite, so mark every square around it right away.
Next, hunt for dark squares that only one spot on the board can light. If a square has a single possible source, the bulb has to go there. Corners are useful too. A 2 tucked in a board corner already has both of its open neighbors decided.
Glance for red after every move. Catching a clash the moment it appears is far easier than tracking it down ten bulbs later.
Sizes and settings
The Type menu offers 7x7, 10x10 and 14x14 grids, each at easy, tricky or hard. If you want something else, Custom lets you pick the grid size, roughly how many black squares appear, how symmetric the walls are, and the difficulty. The N, U and R keys start a new game, undo and redo, and the same commands sit in the menu above the grid.
Controls
| Action | Keyboard | Mouse | Touch |
|---|---|---|---|
| Place or remove a bulb | Arrow keys to move, then Enter | Left-click a white square | Tap a white square |
| Mark a square that cannot hold a bulb | Space or I | Right-click a white square | Press and hold a white square |
| New game, undo, redo | N, U, R | Menu buttons above the grid | Menu buttons above the grid |
Light Up Lamp Puzzle FAQ
Can I play Light Up Lamp Puzzle on a phone or Chromebook?
Yes. A tap places or removes a bulb, and pressing and holding a square marks it as empty. On a Chromebook you can use the touchpad, a mouse, or the keyboard, where the arrow keys move a cursor and Enter places a bulb. The screen can be held either way.
Is it a one-player game?
It is a solo puzzle. There is no opponent and no clock, just you and the grid. Each new game builds a fresh board, so you can keep playing at the size and difficulty you like best.
Which boards are best for a beginner?
Start with the 7x7 easy board from the Type menu. Easy grids can always be solved with pure logic, so you never need to guess. Once those feel smooth, move up to tricky or to the larger 10x10 and 14x14 sizes.
What if I can't finish a board?
Undo and redo let you step back through your moves, so you can return to the last position you trusted. If you just want to see the answer, the Solve option fills in the finished grid for you.
