Thanks to the author for an enjoyable intellectual journey, it's a wonderful series of articles.

Having tried my hand at following the Make a Lisp project ¹, implementing an interpreter in a couple of languages, it's fascinating to see the process of designing the language and compiler from the ground up, discussing various tradeoffs for simplicity, reasons for internal data structure, etc.

In fact, I think I'm learning more about C99 than Lisp - there's something about creating a language (or just following along like me), by necessity it leads to the foundations of computing/programming, the concepts that make up the basis of all languages. It's a perfect (meta)subject for an educational project.

¹ https://github.com/kanaka/mal