­In your house or apartment, you probably have at least one light that is controlled by two separate switches. Whenever you flip either one of the switches, the light changes its state -- if it is on it turns off, and if it is off it turns on.

If you have ever wondered ­how this arrangement works and how each switch knows what the other switch is doing, then read on. In this article, we will solve the mystery of three-way switches!

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