TheÂ Reuleaux Triangle, named after Franz Reuleaux, is this odd roundy triangle, which would hardly seem worth naming after someone, except for one unusual feature: However you turn it, one side is always the same distance from the opposite side. If you were to put a board on a couple of Â Reuleaux Triangles, it would have a perfectly smooth ride rolling on them.Â So what you say? A circle does the same thing? You know how whatever shape drill you use, the holes always come out round? AÂ Reuleaux drill can drill square holes. Not even Chuck Norris can do that.
There are three dimensional equivalents as well:
These shapes of constant width have other uses besides looking funny and drilling square holes. Any time you invent a different way for machines to translate one type of motion into another, you have great potential for new inventions. I suspect this one is under-utilized.