Light Up Lamp Puzzle Unblocked

Light Up Lamp Puzzle is a dark room drawn as a grid, and you are the electrician. White squares need light, black squares are walls, and some walls carry a number saying how many bulbs must sit right beside them. Each bulb throws light in four straight lines, which is generous until two bulbs end up staring at each other. James Harvey wrote this version for Simon Tatham’s puzzle collection. Played unblocked on FreezeNova, it gives you nine preset grids and a custom mode, and the yellow glow spreading as you work is oddly calming.

What Counts as Solved

A bulb lights its own square plus every square in a straight line up, down, left and right, stopping at a wall or the edge. Lit squares glow yellow.

Three things must be true at the same time:

• Every white square is lit, by at least one bulb.
• No bulb is lit by another bulb. Two bulbs can never share an open row or column segment.
• Each numbered wall has exactly its number of bulbs in the four squares beside it. Plain black walls just block light and have no count.

The grid flashes once all three hold. Red highlights warn you of trouble: a red bulb is being lit by another, and a red number has too many bulbs, or too little space left to reach its count.

Grid sizes are 7x7, 10x10 and 14x14, each at easy, tricky or hard. Custom lets you set the size, roughly how many walls appear, the wall symmetry and the difficulty.

Light Up Lamp Puzzle controls

To do this	Keyboard	Mouse	Touch
Put down or pick up a bulb	Arrow keys to move, then Enter	Left-click a white square	Tap a white square
Flag a square as bulb-free	Space or I	Right-click a white square	Press and hold a white square
New grid, undo, redo	N, U, R	Menu buttons above the grid	Menu buttons above the grid

A Solving Order That Works

First pass: the sure things. A 4 needs bulbs on all four sides. A 3 against the board edge, or a 2 tucked in a corner, often has no choice either. Place those bulbs now.

Second pass: the zeros. A 0 means no bulb may touch it. Mark all its open neighbors so you stop considering them.

Third pass: lonely squares. Look for an unlit white square that only one spot on the board could light. Maybe it is boxed in by walls and marks. That spot must get a bulb.

Then repeat. Every new bulb lights a cross of squares, which rules out more spots for other bulbs, which creates new lonely squares. The puzzle tends to unzip from there.

A few mistakes to avoid:

• Forgetting that light passes over marked squares. A mark only means no bulb goes there; it does not block beams.
• Ignoring a red number. Fix it right away, because it usually points to a bulb placed one square off.
• Placing bulbs “to see what happens” on easy boards. You never need to guess on those.

Why It Is Worth Your Time

The rules fit in a sentence, but the deductions can stack up beautifully on bigger grids. It plays nicely on touch screens too. If you enjoy clue-driven grids, try Tents and Trees Puzzle or the shading logic of Range Shading.