A new 3-D viewing system will be described which allows a physician to simultaneously examine multiple CT or B-scan ultrasound scans in their proper orientation in all three dimensions. Several persons can view the display at the same time and there is no need for special glasses. Test images and line drawings displayed on a prototype viewing device exhibit both stereoscopic and motion parallax depth cues characteristic of a real three dimensional object. Operating principles of the device will be outlined and a new 3-D figure/ground illusion will be described.