Cheerful asymmetry

Look at yourself in the mirror. You're probably mostly symmetrical: one eye and one ear on each side of your head, features that are at least roughly even, and any lopsidedness is most likely due to postnatal wear and tear.

Deep inside you, though, you are profoundly asymmetrical, and that asymmetry is essential for your well-being.

And you share this with snails! P Z Myers explains.