ORIGINAL: CGRetired
A little background trivia here... as proven wrong, but it was interesting nevertheless.
When I was much younger.... (very much younger), there was a toy called a ''Slinky''. According to legend...

the slinky was originally an easy way to transport piston rings in World War II. The engines in many of the vehicles were pretty much the same.... consider the mass production of planes, ground vehicles, ships.. (not that ships used the same engines, but the point is there).. the mechanics in both the European and Pacific theaters spent a lot of time rebuilding engines. Part of that was replacing engine rings.
The legend was that engine rings were not manufactured individually. They made these spring-like gizmos... not called The Slinky, by the way, that the mechanic could snip off a circular ''ring'' and put it on a piston, and quickly and efficiently get the engine back up and running.
Now, what I've read, this is nothing more than historical fiction.. however, it does pose interesting viewpoints of how these ''Slinky's'' were used during WWII.
Wikipedia disclaims this. But, we know how they lie!!!
CGr