It is quite common to have a single lightbulb in the home that has two switches to control it. It works so that whichever way the light is (on/off) you can change the state of either switch and it will change the state of the bulb.
For this you could use something like an XNOR gate circuit. (Is this how it is done in practice?).
Is it possible to do the same thing with three switches? So that if any of the three switches changes state it will toggle the state of the light?