When Mr. Potato Head first came out you supplied your own vegetable. If no potato could be procured you could always grab a carrot or an onion. The beauty of this endeavor is that Mr. Potato Head could be rebuilt as Mr. Turnip Head, Mr. Mushroom Head, Dobby, your mom, or Prince Charles. With Hasbro's Mr. Potato Head you are stuck with, well, a plastic tuber.
(Don't ask what slope and wedge parts were used to build this. There was a little bit of poetic license going on. What we can tell you is that the color is tan and there are some technic bricks with pin holes.)