Thanks - what I discovered was that there have been numerous variations on the game, but they all seem to have their roots in
ANIMALS mentioned by
hossman. Every example I could find out there today uses the same tree structure that I independently came up with. Though the original ANIMALS was written in UNIVAC assembly, it is head and shoulders above anything that came after it. Of course, that was probably due to its auther - John Walker. In any account, his assembly has given me some ideas, though I am not sure it is worth the time an effort. My goal was to replicate the functionality of the game I played as a kid (which I did), not that of a UNIVAC assembly programmer (which appears to be way cooler).
Thanks for the input and congrats on a prestigious child hood!
