M.C. Escher is well known by his artistic regular plane divisions and artworks of impossible constructions. But he also created several artworks with irregular mosaics, which consist of shapes of various animals. Two of them you can see below. As you can see every animal in mosaics are fit all its neighbours without any gaps.
Today may artists follow the way of Escher in creating complex mosaics. Images of Bobby Bogl are worthy, which you can see below. Take a notice of how all parts of his images accurate match to each other.