In theory, this could one day provide a key component of any nanoscale electrical circuit-a way to mechanically turn the current on and off or change its direction.

He was just sort of interested in getting the Apple II on a printed circuit board so he could have one and be able to carry it to his computer club without having the wires break on the way.

Common always circuit design are two ways, one is internal clock way, another way to external clock way.