Number 9 (Story #4), November 20, 1990 by Phillip F. Schewe and Ben Stein CHAOTIC CONDITIONS DO NOT INSURE EFFICIENT MIXING of two viscous fluids. Julio Ottino of the University of Amherst (413-545-0593) has discovered that when spots of dye are injected into clear fluids and then stirred, some of the spots are quickly stretched out and folded in a chaotic fashion while other spots, located in certain islands of stability called "periodic points," will hold their shape. These studies are potentially important for certain industries (paint mixing and bread baking, for example) where thorough mixing of two or more fluids is crucial. The principles may apply also to tectonics, where the "fluids" are shifting and subducting crustal plates. (Science, Nov. 2.)