First replicating organism created in simulation

Summer Project: To illustrate the most popular stories in the NewScientist. The first one up is a story on how a computer simulation has produced the first self-replicating organism. I tried to find an animal shaped as something that can tessellate, but all I could really come up with (without knocking off Escher's fish illusions) was some snakes. Still a work in progress.... haven't got them all fitting together just yet. Also thinking they need something to make them more interesting......