richly-layered erudite and intricate gems in a working life in which he retired at 49 is about as likely as learning in a few years that Billy Carter, Jimmy's brother, invented the Internet, thought up Twitter, and did both theoretical and initial lab work resulting in three Nobel Prizes ...
If you want an easy answer, a shamrock is a three-leafed clover. The problem with that answer is that there are a lot of types of clover, and almost all of them have three leaves. In fact, it's so well-known that clovers have three leaves that true clovers have the scientific name...