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Objective
Place light bulbs so every white cell is illuminated, with walls blocking the light. A classic 'Akari' logic puzzle — no two bulbs may shine light on each other, and the goal is lighting every white cell using as few bulbs as the walls allow.
How to play
- Tap a white cell to place or remove a bulb.
- Light travels in straight lines until it hits a wall or the edge.
- Light up every white cell to win.
Light-Up Top 5
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Light-Up
Tap white cells to place bulbs. Light travels in straight lines until blocked by a wall. Light every cell.
⏱ 00:00
🎉 Every cell is lit!
🎉 Solved! Moving to the next puzzle…
About Light-Up
Light-Up is a small logic puzzle played on a four-by-four grid with a couple of dark wall blocks. You place bulbs on white squares, and each bulb beams light in straight lines up, down, left and right until it hits a wall or the edge of the board. The aim is to get every white square glowing. Because the beams stop at walls, you have to think about line of sight, which makes it a tidy exercise in spatial reasoning.
Tips and strategy
- Start with squares that can only be lit from very few places, such as a cell hemmed in by walls or edges. Those squares often force a bulb right where you stand.
- Corners are efficient spots. A bulb in a corner lights both its row and its column, so it covers a lot of ground along the board edges.
- Look at how the two walls cut rows and columns into shorter segments. Each segment needs a light from somewhere, so count your segments.
- Tap a bulb again to remove it. Moving a bulb is cheap, so experiment, and watch the pale yellow squares to see exactly what is already lit.
- Press Check Solution when you think you are done. If the board still has dark squares you will be told, and a Show a Valid Layout hint is available if you are stuck.
What it exercises
Light-Up trains spatial reasoning and logical elimination. You imagine light travelling along lines, predict where it will stop, and revise your plan when a bulb leaves a square dark. That mix of visualising and checking is a friendly workout for planning skills.
Frequently asked questions
- How does light travel in Light-Up?
- Each bulb lights its own square and then sends light up, down, left and right in straight lines. The light keeps going until it reaches a wall block or the edge of the grid.
- How do I win Light-Up?
- Place bulbs so that every white square is lit, then press Check Solution. Wall squares do not need light and cannot hold a bulb.
- Can I take a bulb back after placing it?
- Yes. Tap the same square again to remove the bulb, or press Reset to clear the whole board and start the layout over.
Try next
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Move a chess knight so it visits every square on the board exactly once. A classic chess puzzle — using only legal knight moves, the goal is covering the entire board without ever landing on a square twice.
Unblock
Slide cars out of the way to clear an exit path for the red car. Every car can only slide along its own row or column — the goal is clearing a path so the red car can slide all the way to the exit.
Reflex Beam
Place diagonal mirrors to redirect a laser beam into the target sensor. Only diagonal mirrors are available, so the goal is finding the placement that redirects the beam through exactly the right sequence of turns to reach the target.
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