Question about cat breeding, breeds, and maybe genetics?

[imported_k_d]

I was wondering how what seemed to be two American Shorthair cats (related, one a calico, not entirely sure on the breeds) produced offspring that included a Tiffany and what appears to be an Ojos Azules, plus a variety of other cats, aesthetically? Is there some kind of gene pool that cat breeding works from? Is it that the two parent cats weren't purebred or something?