It gets so much worse than that. Is an electrical switch a door? It's a straight bit that bridges a gap and rotates on a hinge. How about gears? Do gears count as wheels? They're round, they spin, and they apply mechanical forces on their perimeter.

You can actually attempt to answer a question like, "are there more dogs or cats?" because dog and cat are relatively specific. You might quibble whatever wolves or lions count, but adding wild animals to the numbers won't change the math much. But door or wheel? Those are objects much harder to pin down.