This applet simulates viscous, 2D, flow between rotating cylinders. Operating instructions are available as online help. For further information about chaotic and nonchaotic flows in this system, see, e.g. Bresler, L., Shinbrot, T. Metcalfe G. & Ottino, JM "Isolated Mixing Regions: Origin, Robustness and Control" Chem. Eng. Sci. 52 (1997) 1623-36.