There's a couple of very cool things going on with this dance routine. First off, it's based on the principles of fluid dynamics—physical laws that predict the movement of liquids and gases.*
Second, the dance you're watching was recorded live. That means all the nifty "70s Sesame Street"-style tracer effects on dancer Hope Goldman's body, and the visual elements tracked to her movements, weren't added in later. Instead, Goldman and visual artist/programmer Andrew Moffat used "infrared lighting and a custom-modded, $40 webcam along with custom software running on the GPU."
This dance was Goldman's master's thesis for her program at the University of Illinois at Urbana Champaign. Great work!
*Awesome fact that I always forget isn't necessarily common knowledge: The gases that make up Earth's atmosphere and the air you breathe are fluids
behave like liquids. So fluid dynamics doesn't just affect things like oil running through a pipeline—it also governs how hot air from your furnace flows through your house, and how weather patterns move around the globe. (Screwed up the wording there at first, with my layperson's tendency to get "fluid" and "liquid" mixed up. Sorry about that.)
(Via Ferris Jabr)