Yeah, kind of like a less linear version of Metamorphose http://www.bancodedadosvisual.hpg.ig.com.br/Escher-Metamorphose-II.jpg
Was it 'Fish is Fish' by Leo Lionni? The book is about a fish who is wants to explore land but can only breathe in water. His best friend is also a fish, but as they grow they learn that his friend is a tadpole. The tadpole who grows into a frog and eventually goes out onto the land. The frog returns to the pond a few weeks later and reports on what he has seen. The frog describes all kinds of things like birds, cows, and people. The books illustrations are the fish's representations of each of these descriptions, in that each is a fish-like with added things like wings, udders and fish that walk on their tail fins. It's a great book that shows the creative opportunities and dangers that can occur when people form their knowledge on the current set of information that they have. It's a good book, actually. My children love it and I did as a child. The copy I have is well over 30 years old. The pictures remind me of that book.
