racket events video 1.9/4 --- smoother events
Channel: Danny Heap
Date: 2013-01-28

Video from http://www.cdf.toronto.edu/~heap/Racket/events.html shows how to get that barracuda rotating in a more circular fashion, rather than flopping about.  We need to add parameters to on-tick and define a new function rotate-second to update our image model.