This appears to be an animated form of line integral convolution. Cabral and Leedom paper's from SIGGRAPH '93, Imaging Vector Fields Using Line Integral Convol

This appears to be an animated form of line integral convolution. Cabral and Leedom paper's from SIGGRAPH '93, Imaging Vector Fields Using Line Integral Convolution (PDF): http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.115.1636&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.115...