Ref: Clojure from the ground up: welcome
Really neat article (and series) about program design from first principles.
I loved the emphasis on motivation and simplicity.
Lisp is ridiculously simple to write computation. This post does a great job at developing intuition about programming. I found a lot of traces from SICP in the mental model.
You could think of this structure as a tree–which is a provocative idea, because languages are like trees too: sentences are comprised of clauses, which can be nested, and each clause may have subjects modified by adjectives, and verbs modified by adverbs, and so on.
Extremely powerful concept.