All-Lights Puzzle
Author: Yasunari Hiramatsu
Script: goobix.com
Turning all 25 lights on
The objective of the game is to turn all 25 lights on. Clicking a square will toggle its light (as well as the lights of all horizontally and vertically adjacent squares) on and off.
You can accomplish this in just 15 clicks.
If, after several attempts, you fail to illuminate the entire grid, you can find one of the four possible solutions discovered by Luis Silvestre, a student of Computer Science and Mathematics at UNLP, right here.