A laser or other substantially collimated light source is operatively
connected to a reciprocating driver that causes a beam from the laser to
sweep across a conveniently viewable surface at an adjustable frequency,
thereby tracing a pattern on the surface between a plurality of beam path
boundaries. The beam's direction change at a beam path boundary generally
serves as a visual indication of a musical beat. The laser may be
positioned and/or aimed to project the beam on any surface. The frequency
of driver reciprocation (i.e., the tempo) may be adjusted to correspond
to one of a range of typical musical tempos, thereby providing the
functionality of a metronome but with the novel and useful additional
element of a projected beat image.