Gravestone of Elija Bond, Inventor of the Ouija Board

Elijah funded it, but it was actually Charles Kennard that adapted it into something like we'd recognize today. Bond insisted on the patent and always claimed to be the inventor though. I only know this because I was listening to the Stuff You Should Know podcast about Ouija Boards this morning; I've never actually used one.

Can you patent an ouija board? How do you demonstrate its function?