Light Up

from Simon Tatham's Portable Puzzle Collection


Drag to resize the puzzle. Right-click to restore the default size.

Link to this puzzle: by game ID by random seed

This puzzle did not finish loading. Refresh the page and check whether the local JS and WASM files were served correctly.

If the problem continues, open the browser console and network panel to see which asset failed.


Place light bulbs in the grid so as to light up all the blank squares. A light illuminates its own square and all the squares in the same row or column unless blocked by walls (black squares). Lights may not illuminate each other. Each numbered square must be orthogonally adjacent to exactly the given number of lights.

Click on a square to place or remove a light. Right-click to place a dot indicating that you think there is no light in that square.

Full instructions | Back to main puzzles page


(comments to anakin@pobox.com)
(thanks to chiark for hosting this page)
(last modified on Mon Mar 9 01:42:11 2026)