Static type checking in Lisp
Article about experimenting with static type checking in Common Lisp.
A Twitter thread about issues with Emacs on macOS and how to work around or plain solve them.
Honestly, as someone who's 100% Emacs/macOS, I'd not really noticed any of these -- but I always run Emacs as a fullscreen application in its own desktop space.
Online course where you can teach yourself how to use a sliderule.
One day.... One day...