Now, to bring this back to the round/square wheels thing - yes, as Stirling posted in the comments, the round wheels are optimal and thus the most likely solution. However, I'm going to have to disagree with the idea of there being only one optimum solution while agreeing with it (bear with that contradiction in terms for a moment.)
It all depends on what the goals are. To repeat the quote: "All who make wheels, make them round." Making a round wheel is reliant, to a degree, upon the intention to make a wheel. If the intention is different - say, locomotion instead - the results begin to vary. I realize this seems self-evident. Where importance comes in is in realizing when we're trying to make wheels and when we're just attempting to move from point A to point Z.
Part trois coming.