Symmetry is certainly the key word isn’t it. Symmetry in the human body (especially the face) is fundamental to our appreciation of beauty; they were actually talking about that on the radio yesterday, saying that beautiful people were more likely to earn a higher salary. But why would symmetry in the human body be important? Could it be that asymmetry (in the extreme) was linked to deformity and illness... although interestingly people with deformities seem to have been treated with respect in some early cultures.

And is it reasonable to conclude that asymmetry in a hand tool might cause it to be less functional...