I’ve just read your fascinating SF ‘blog’ (how I dislike that word!) about the large amount of careful organising that goes into building SF versions for many platforms. The ‘Levitating’ application sounds brilliant. How sensible to write your own! That’s often the only way to obtain systems that do exactly what you need. So many businesses purchase proprietary management systems and have to change what they do to fit in with the software, instead of the other way round!
I was particularly pleased to read that you‘ve written ‘Levitating’ in Fortran. It’s a superb language, that much of the world misses out on out of a misplaced belief that it belongs in the 1960s/70s and is now obsolete.
I recall that Fortran 66 for Pr!mos was written in Fortran66.
Definition of “recursion”: