Da Vinci was a painter who sketched some neat but impractical things.
Hero of Alexandria (funny how all the geniuses have places of origin instead of last names) came centuries before him and outdid him in inventions produced. First steam engine. Wind power. The vending machine. A programmable binary machine that could do a full ten minute play, including sound effects, all on it's own.
To continue with the more obscure side of history, I also nominate
Von Berlichingen, who went on to fight wars for nearly forty years
after his arm was blown off by cannon fire. He could do this because he got a prosthetic years ahead of it's time (I think even most modern ones are a poor substitute for his, unfortunately no one knows who made it). He also invented the phrase "kiss my ***."
So, yeah.
