Research carried out at the University of Pennsylvania has definitively measured and described the Brownian motion of an isolated ellipsoidal particle, completing a path laid out by Einstein 100 years ago when he first described rotational Brownian motion for spheres in water. Brownian motion, the tiny random movements of small objects suspended in a fluid, has served as a paradigm for concepts of randomness ranging from noise in light detectors to fluctuations in the stock market. Using digital video microscopy, the researchers directly observed the twisty random walks arising from the combined effects of random rotations and displacements of ellipsoids in water.