"While consulting for Holt/Rinehart I considered the typical hydraulic analogy to explain electric ciruits. I found a better one: electricity is like the molecules in a loop of rope wrapped around pulleys. It's like the rubber of a conveyor belt: when the drive roller turns, all the other rollers turn as well. When internet came along, I started pushing this analogy all over Usenet forums. It slowly caught on. Then I came up with another version: electricity is like a rubber bicycle tire: push it in one place, and all the rubber must turn as one. Look around the www today, and see how far these ideas have spread."