Sometimes I wonder if humans also have an innate tendency to design objects with faces in them. We find faces in the objects in our everyday lives because we all have this Pareidolia condition, but what if we also have a subconscious reverse Pareidolia where we want to put faces on the things we make? It would explain some objects quite well.
Mokalus of Borg
PS - It is a pleasing visual arrangement, in either case.
PPS - So it would be no surprise to me if we naturally arrange things that way as well as looking for that arrangement.