update#4: Completely removed sound. Update#3: Volume reduced. Update#2: added control to turn off sound. Update#1: added sound. The goal of Lights Out puzzle is to switch all the lights off, preferably in as few button presses as possible. Selecting one of the lights will toggle it and the four lights adjacent to it (i.e. left, right, top and bottom) on and off. (Diagonal neighbors are not affected.)

Lights Out screenshots: