(currently migrating from https://github.com/wasserfuhr/AllHashes/blob/master/Think.java )
cf http://www.slideshare.net/rainer/aigame
We agree on a very minimalistic RuleSet: a cube of bytes. The preferred size is 2^n, depending on your available memory.
E.g. for n=8, the edge length is 2^8=256. The cube has 256x256x256 bytes or 16MegaBytes or exactly 16777216bytes.