Not the best idea to do puzzles while tired. Best case scenario it saves doing them tomorrow when I could be plugging away at NixOS, which I'm feeling lost at but I'm ok with that, and watching Sunday Brunch. It would be great if there were a NixOS book in the style, and quality, of a 1985-2010 O'Reilly book because it would be less mucking about. I have literally no compelling reason to learn about NixOS in depth but I'll carry on because I'm enjoying the novelty/challenge/puzzle/learning.