I have been playing around with Conway's Game of life and recently discovered some amazingly fast implementations such as Hashlife and Golly. (download Golly here - <http://golly.sourceforge.net/>)

One thing that I cant get my head around is how do coders implement the infinite grid? We can't keep an infinite array of anything, if you run golly and get a few gliders to fly off past the edges, wait for a few mins and zoom right out, you will see the gliders still there out in space running away, so how in gods name is this concept of infinity dealt with programmatically? Is there a well documented pattern or what?

Many thanks