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...
With just 15 clicks you can accomplish it.
If after several attempts you fail to illuminate the whole chequered board, you will find one of the four possible solutions found by Luis Silvestre, a student of Computer Science and Mathematics at UNLP here.
Mentes en Blanco