I love Simon's anecdote of using his wife and children as the stack as he developed IPS.
This eventually was replaced by GPS, which has a good description in Norvig's Paradigms of Artificial Programming, here: https://github.com/norvig/paip-lisp
https://sites.google.com/view/elizagen-org/eliza-clones
Although IPL is a direct Lisp predecessor, it can't be easily mapped to Lisp. Indeed, Lisp and IPL-V were contemporaneous for about 5 years, but Lisp was so much simpler and more elegant that it rapidly supplanted IPL. As a result, Ed Feigenbaum and I are probably the only living person who know IPL (and I only barely know it as I just learned it in the past few months!), whereas Lisp has been essentially endemic for 60 years! (I'm hoping I'm wrong that Ed and I are the only folks who know IPL. If you know of a native IPL speaker who I could talk to, I'd love you to DM me!)