Comic artist Rube Goldberg created a lot of crazy contraptions on paper that would make the simplest jobs long and complicated via a string of interconnecting gadgets, animals, and tools. These gimmicks seemed like a natural for a model kit, someone must have reasoned, and a series of kits were issued that copied the Goldberg genius. If properly built they would perform the task at hand. In the one I'm showing it's a way to scrub grandpa's back. I've never had one of these kits, or even seen one, but it looks like it would be fun to build one.