Scattered against a black background, vivid blue, beige, and orange dots—32 of them to start—commence an amazing dance. They quickly double in number, shrink, and double again. They fill one pole of a slowly spinning, invisible globe. As they continue to multiply, becoming hundreds, then thousands, of little points, they swarm, covering the globe evenly in brilliant blue with specks of orange flashing in and out of existence. The dots then crowd the equator and meld into the shape of a fish embryo.

The video is like computer-animated pointillism. But rather than a piece of digital art, it represents a scientific feat—a stunning series of images that reveals the development of a live zebrafish embryo over 24 hours. Each cell in the embryo is represented by a single dot, colored blue when still or moving slowly and shifting to beige and then orange when migrating more quickly.

Illustration: Josh Cochran