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Lights Out

Lights Out is a commercially marketed (by Tiger Electronics) product whose analysis admits a linear algebra framework analogous to that of Merlin's Magic Square puzzle. It consists of a 5×5 array of buttons that may be in one of two positions: on or off. Pressing a button changes its state and that of its vertical and horizontal neighbors. For a given configuration, the task is to turn all the buttons off (out.)


The Theory

Copyright © 1996-2008 Alexander Bogomolny