Picture a dark room split up by black pillars. You have as many lamps as you want, but they are fussy: no lamp may sit in another lamp's beam, and some pillars insist on a set number of lamps right beside them. Light Up Lamp Puzzle unblocked gives you that room as a small grid you can solve in a browser tab.
The puzzle comes from Simon Tatham's Portable Puzzle Collection, with this one written by James Harvey. Each board is generated fresh, so you never run out of new rooms to light.
How to play Light Up Lamp Puzzle
A bulb lights its own square and shoots light straight up, down, left and right. Each beam keeps going until it reaches a black square or the edge. Squares that are lit turn yellow, so you can see what is still dark at a glance.
To win, three things must be true at once. No white square is left dark. No bulb sits inside another bulb's beam. And every black square with a number has exactly that many bulbs touching its four sides, not counting diagonals. Plain black squares only block light and have no count to meet.
The Type menu sets the grid size and difficulty, and the Custom option lets you adjust the board further. When a bulb or clue breaks a rule it turns red, which is a quick signal to back up.
Controls
| To… | 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 |
Tips
- Start with the zeros. A 0 means none of its neighbors can hold a bulb, so mark all of them before doing anything else.
- Count open sides. When a clue's number equals the free squares around it, every one of those squares gets a bulb.
- Hunt for lonely squares. If a dark square can only be reached from one spot on its row and column, that spot must hold a bulb.
- Mark freely. The dot marks cost nothing and stop you from second-guessing squares you already ruled out.
- Use undo instead of restart. The puzzle keeps a full history, so step back a few moves when a red warning shows up.
Light Up Lamp Puzzle questions
Do diagonal bulbs count toward a number?
No. Only squares sharing a full side with a numbered wall count. A bulb on a diagonal has no effect on that clue.
Can I play it on a phone or tablet?
Yes. A tap places or removes a bulb, and pressing and holding a square adds a mark that says no bulb goes there. The grid resizes to fit your screen.
Will I ever have to guess?
On the easier settings each board can be solved by logic alone. Harder settings need deeper chains of reasoning, but the generator still builds puzzles with a single answer.
What if I get completely stuck?
The menu has a Solve button that shows the finished board. You can also hit Restart to clear your bulbs and try the same grid again from scratch.
