Sarah Lynne ReulEffects: Vortex
This effect was one of the hardest for me to grasp – we studied vortexes, including water vortexes, tornados, fire whirls, etc.
I do like the way this turned out, although my instructor pointed out that it has a sort of “spinning plates” feel to it. Here’s a page of exploratory sketches:
I almost chickened out in favor of a jellyfish animation, with little vortex eddies coming out (instead of tackling the tornado effect): 
Sarah Lynne Reul 
Awesome!