I keep a notebook of ideas I want to pursue later. A lot of times if you don't write them down they'll be forgotten over the years, unless they're of major importance.

Over enough years, they will be forgotten, just like the names of the people you went to school with, unless you've got a way to rehearse them.

So a million years ago (the mid-90's), I was working with Doug Hofstadter and I had some ideas I wanted to follow up. Over the intervening years of raising a family, none of which do I regret, I never had the opportunity to actually do that - but I've done a lot of pieces of it, sometimes forgetting exactly where it fit into that original big picture.

Unfortunately, a lot of those pieces were logged on paper, but I've got electronic notes from about 2011 on, and a good content index has come in really handy for pulling out earlier ideas on various topics.

I've been working on that for the past year, and also scanning in a lot of the paper notes and starting to transcribe some of them. Looking back, there are some ideas I have every five or ten years, every time thinking I'm quite innovative.

Now that I've had the time to collate all that (and to read an absolute metric ton of literature I missed, an ongoing process), I've started to make consistent progress towards my original goals.

But just as a for instance - I have my readings and research bibliography from 1995 in machine translation. Most of that is dead as Carthage from a technical standpoint, obviously, but the philosophy has been invaluable as a starting point for recalibrating where I'm going.

But I've also got a lot of notes on related projects and just noodling thoughts I've had over thirty years of driving kids around in cars. I think the most important aspect of this is just keeping your mind active and focused on the things you find interesting, even if you don't have anything like the time you'd need to pursue them properly. Because sooner or later, the stars will align and you will. And when you do, your notes will be absolutely vital.

But I'm kind of obsessive about notes, so your mileage may vary.

I’m envious, reading EGB in the ‘70s is what put me on the path of computer science. I may yet try copycat or other creative analogy project in Elixir. I have the time, I’m retired :)