He certainly is a genius, and you're right that the first version of TeX was not written using literate programming tools; he planned it out on paper instead an

He certainly is a genius, and you're right that the first version of TeX was not written using literate programming tools; he planned it out on paper instead and programmed it using SAIL. He had a nasty bootstrapping problem since he needed TeX to exist before he could write a first version of WEB. But once he had a first version of TeX (TeX78), he built WEB, and then he re-wrote TeX from scratch (TeX82) in a different programming language (Pascal/WEB instead of SAIL).