OK, here's one for the EE's or EE hobbyists out there. This one is brought to you by my ME major and EE hobbyist (who also works in the theater) friend.
So, we just recently installed a new direct control system for four circuits in our studio theater. It uses 4 SPDT toggle switches that are enclosed in a small remote. There are only FIVE wires going from the control box to the wall. How was this done, I ask you? We had only five wires to control four switches, and on the other end of each is a latching relay, and requires a signal to turn it on and a different signal to turn it off. So, this would imply 9 wires: one to send power to the remote, and 2 wires for each switch: one for off, and one for on. We enclosed no chips or complicated electronics in either end. It's very simple, hardly any more components, and we used no more than one other type of component.
We needed 9 wires, but only had 5. And somehow it worked! So, how'd we do it?