This movie, accelerated 15x, shows the formation and the dynamics of the living crystals. The active particles spontaneously assemble in crystals which merge, break apart and reform. The crystals dissolve when the light is shut and reform when the light is on again. This video relates to a paper that appeared in the Jan. 31, 2013, issue of Science Express, published by AAAS. The paper, by Jeremie Palacci at New York University in New York, N.Y., and colleagues was titled, "Living Crystals of Light-Activated Colloidal Surfers."