Maybe have a look at this: http://demonstrations.wolfram.com/preview.html?draft/46249/000012/FourierDescriptors http://demonstrations.wolfram.com/preview.html?d

Maybe have a look at this: http://demonstrations.wolfram.com/preview.html?draft/46249/000012/FourierDescriptors http://demonstrations.wolfram.com/preview.html?draft/46249/0... Which may be how they did it.