If you bend the edges of the cube outwards a little, then the hexagon becomes a circle. Or, imagine the volume which is created by the intersection of four cylinders passing through a central point. The result looks like a slightly-swollen cube. The edges are segments of ellipses. This cube can roll, if placed upon an axle.
Triangular wheels look even stranger.
I wouldn't be suprised if there was some obscure article about them in a journal somewhere. Created and maintained by Bill Beaty .