“…What we’re going to do in this essay is understand what that half page of code means, and what it means that Lisp is the Maxwell’s equations of software. However, we won’t literally work through the half page of code above. Instead, we’ll do something much more informative: we’ll create a modern, fully executable equivalent of the code above. Furthermore, to make this essay accessible, I won’t assume that you know Lisp. Instead, I’ll teach you the basic elements of Lisp…”
http://www.michaelnielsen.org/ddi/lisp-as-the-maxwells-equations-of-software/