Abstract: The disclosed device is a combination of horizontally and vertically guided members which form an input area and an output area so that perspective views of objects in the input area are created in the output area by the projections of the visible points of the objects onto a plane perpendicular to the line of sight, along lines from the viewpoint. In the input area, a horizontally guided bar has a vertical guide therein. Two members are hinged together at a viewpoint or separately at viewpoint and modified viewpoint and the ends of the members which fall in the input area are slideably connected to the guide in the horizontally guided bar. One end of the member falls in the output area and is horizontally guided while the other end of the second member also falls in the output area and is vertically guided. An output bar system is connected to these ends to form an output point in the output area.