A light switch is the simplest of electrical devices. Flip the switch, electricity flows. Flip it again, electricity stops. Lights on, lights off. That’s great for a small room with one entrance.

Christian Nguyen: This car lights up with something called LumiLor. It's not LED light, but paint. And not just glow-in-the-dark paint, but a special kind of paint that turns on and off by ...