racket recursion video 1/6 --- triangle recursion
Channel: Danny Heap
Date: 2012-06-08

http://www.cdf.toronto.edu/~heap/racket_lectures.html   Video on how to build Sierpinski's triangle using recursion, since it is built using scaled-down copies of itself.  The racket definition serp refers to itself three times, allowing you to easily build something quite sophisticated.  More videos:

www.cdf.toronto.edu/~heap/Racket/recursion.html    See also
www.cdf.toronto.edu/~heap/racket_lectures.html