Jonah Goldberg's Odd Links Gal. Conservative Virginia Grandma.
This is not a proper "chain reaction"!! The classic experiment is to fill a room with mousetraps, each holding two ping pong balls...thus each mousetrap triggers TWO more. The purpose of the thought experiment (or real one, if you have that many traps and ping pong balls) is to illustrate why nuclear fission produces a bang.This is just a sequential triggering, which would not cause a nuclear explosion.