This video shows a fruit fly embryo's first hours, during which time a single cellular nucleus divides into thousands. Thomas Gregor's efforts to label one of the embryo's proteins with a fluorescent material allowed the nuclei's behavior not only to stand out on film, but also to become open to mathematical analysis, as represented by the scientist in the background. The film, which Gregor produced with the assistance of Jean-Baptiste Boule and Matthieu Coppey, won the video prize in Princeton's 2006 Art of Science competition.