Thank you the retracement link. I was aware of the link to the Golden Ratio and many of places in the natural world and artistic endeavours where it crops up.

As a teenager I was fascinated by the GR for several years. I wrote my first recursive Fib routine when I was 15 in an interpreted assembler-like teaching language called BBCX (that was itself implemented in an interpreted BASIC and ran on a TOPS-20 mainframe at a Uni miles away).

Runtime was strictly limited, so I had to get special permission to have the program run over a weekend in order for it to calculate the first 23 terms (16-bit signed integer limit). I don't remember how many hours it ran, but it was a looong time.