Up until about here, this is the same lesson I recently rewrote that's still in PR land. The reason I decided to re-write it, and I have the same comment here, this is not zero entry. It's front-loaded with a lot of unnecessary history and technical talk about how things were created, with lots of notes about how incomprehensible it all is...It's not that history is unimportant, but IME with real zero entry people, this is all terrifying.