I've been looking for a particular z80 code listing, looks like I don't have it. I don't have a lot of stuff from the 80s and 90s, and most of what is o have is 1981 through 1994.
I used to keep cheap spiral bound notebooks open next to my computer (I've switched to rules pads) to scribble instant notes ("Mary called phone 12345677") and rough out ideas. I had no idea they'd be so interesting later.
(The current method is 10x10 grid pads, shopping lists, ideas, code fragments, scribble drawings, .... Meaningful ones go in project binders but crossed off lists go on the trash.)