A summary of the rules:
If a square has 2 or 3 neighbours, then it will turn white (or stay white).
If a square has more or less neighbours than that, it will turn black (or stay black).
How to play:
Click in the black area to turn a few squares white.
Then press run. Press pause and it will stop running.
To advance by just one turn at a time, press "once".
Sean wrote for various Amstrad magazines in the distant past. I recognise some of the screenshots at his website as games that I played back in the day.
Really good work. He says he was only a kid back then.
My book "Choose Your First Product" is available now.
It gives you 4 easy steps to find and validate a humble product idea.