Thank you as always for your thorough replies. I’ll split them up next time. I took notes while watching, then compiled my questions not answered by the end.
(Greenspun only had 1 “rule”, about complex programs containing an ad-hoc subportion of Common Lisp (later amended to point this finger at Common Lisp itself 
), called it his “tenth rule”, but had no other rules. Which one were you referring to with the seventh?)