Lets say my company make a new shape of Rubik's Cube (a round ball twisty puzzle) and we call it a "Ball Cube" (my company is called "Puzzles" so its a "Puzzles Ball Cube").
I patent the "Ball Cube" and start selling it...
20 years later the patent expires and lots of other twisty puzzle manufacturers create the "Ball Cube" and call it their own brand so lets just say "Rubik's Ball Cube" and "LanLan Ball Cube" and "China Ball Cube".
Are they free to do so? do i legally own copyright for the "Ball Cube" phrase or the design of the original? Or would I have to file for a trademark?
Can a physical object like this twitsy ball cube be protected under copyright after the aptent expires?