Abstract: A collimated light source, preferably coherent, is directed at an optical system comprising a plurality of controllably rotatable mirrors, the source going from one to the next in seriatim, and each mirror being mounted a small number of degrees "off" the optical axis, so as to oscillate upon rotation. With the rotational speed of each mirror individually controllable, a substantially infinite number of patterns can be generated. Further variations in pattern generation can be achieved with a beam clipper, pulse modulation by an analog (e.g. audio) signal, and/or other known beam-modifying devices. A preferred embodiment is adapted for entertainment purposes and employs a low-power laser and three mirrors. Other applications include pattern-recognition testing of individuals for optometric or psychological purposes.