Some of the things you will need to understand to be able to write programs in the Scheme programming language, which is a type of Lisp. Andy Balaam introduces pairs, lists, and navigation through lists using recursive procedures, before discussing the map and foldr procedures, which you will use in most programs. If you're new to Scheme, it's probably worth watching http://youtu.be/byofGyW2L10 first. The slides are here: http://www.artificialworlds.net/blog/2012/05/25/scheme-2-basics-pairs-and-lists-video/