Nanopond: The world's smallest and simplest artificial life virtual machine

From the site:
"Nanopond is the world's smallest and simplest artificial life virtual machine. It is a "corewar" style artificial life system of the same class as Tierra, Avida, and Archis but is so simple and tiny it fits in only one .c file! By comparison all three of these others are absolutely huge.

It is simple and no-frills, and to make it work you must compile it."