I've often heard ( and said ) that to retain skills and knowledge it's a matter of either " use it, or lose it ".
I know from hard earned experience ( 75 odd years and counting ) that this axiom is true.
Some Stuff I 'knew' 10-20 years ago, and haven't really re-visited , I now need to re-study to be comfortable with using. It's embarrassing to read something interesting posted somewhere and realise that you wrote it, and don't still have the knowledge fresh in your brain. !!
I came across this site today and thought I'd share it [ before I forget ].
added: some of the images are interactive, don't be afraid to have a play
perhaps it will help.
https://ncase.me/remember/Regards,