Hi, I'm an undergrad doing a summer research project on Graph C* Algebras, and have been trying to come up with examples of Cuntz-Krieger E-families which are non-isomorphic for some directed graph E. I know that there are various situations in which all non trivial C* algebras are isomorphic, but I cannot come up with an example of two non trivial algebras generated by different Cuntz-Krieger E-families which aren't isomorphic. Can anyone help me out?