This paper presents a method to visually display, in true three dimensions, light spots representing objects or targets. They can move in three spatial directions within a specified volume as directed by incoming electronic information. Spots of light positionable in the X and Z directions are flashed onto an oscillating screen moving in the Y direction. If the flashing of spots is synchronized with the position of the screen, the spots, generated by a cathode ray tube (CRT), can be made to appear stationary in space. The spots are flashed onto the screen through an optical system consisting of mirrors, a collimating lens, and a focusing lens. The translucent screen and focusing lens oscillate together in a direction perpendicular to the planes of the screen and focusing lens. Since the screen and focusing lens move together, the focal distance is held constant. A key to the method is the mechanical drive system for the reciprocating motion of the screen and lens. The drive provides: (1) theoretically perfect rigid body dynamic balancing to minimize vibration, shock, and noise; (2) simple and low power mechanical drive system, offering continuous unidirectional rotation; (3) constant inertial load; (4) harmonic motion, providing for simple data inputs; and (5) low friction losses.