Engravings like these posed problems for the theory of separate creation for at least two reasons. They suggested that biological flora and fauna were much more diverse and widespread than had been previously imagined, and they pointed out remarkable similarities among creatures of different types, even across wide generic boundaries. It was curious enough that all insects had six legs. Even more significantly, all creatures with eyes tended to have two eyes, one on either side of the head. That suggested not only a pattern, but perhaps a common origin..