I do tend to agree that unicellular life has a mind boggling diversity of forms and you can find similarities to most things, simple or not-simple :) That said

I do tend to agree that unicellular life has a mind boggling diversity of forms and you can find similarities to most things, simple or not-simple :) That said, humans have a very specific notion of "simple shape", intuitively incorporating symmetry into it. Symmetry is far from guaranteed in mathematics (although mathematicians, being human, also tend to search and study symmetric things). Even in the most symmetric objets - let's say groups, there are many more non-abelian (i.e. not commutative ab != ba) groups than there are commutative groups.