This applet is based on a game that has several variations. The version presented here is common, though more complicated editions exist (such as lights with more than two states). Given a random starting configuration, the goal is to find a sequence of "moves" that will turn all lights out (so all blocks are black). Pressing one light will change its state, as well as the state of its four nearest neighbors.
Not all starting configurations have solutions. This applet provides several choices for starting configurations - not all of them have solutions.
A special thank you goes out to all Math 150 students in Spring 2016 for their puzzle contributions!
Using the Applet
Tap a square to flip its "switch" along with its nearest neighbors. The puzzle is complete when all squares are black.
About this Applet