Thanks for sharing this. There are lots of things like this--foundational, simple, background knowledge that I never fully grokked, and this took me through it

Thanks for sharing this. There are lots of things like this--foundational, simple, background knowledge that I never fully grokked, and this took me through it in a much more straightforward and practical way than I would get from, e.g., Wikipedia, and in a more discrete, digestible chunk than if I tried digging through college textbooks.