1. “Mirage” is a registered trademark of its manufacturer, Opti-Gone International, Ojai, CA 93023 USA. http://www.optigone.com.
2. The Mirage toy is listed on the PIRA (Physics Instructional Resource Association) database of physics demonstrations as number 6A20.35. See, for example, http://www.physics.brown.edu/physics/demopages/Demo/optics/demo/6a2035.htm.
3. We obtained these results by supporting the upper mirror in a fixed horizontal position from its edges. The lower mirror was placed on a lab jack and slowly lowered to reveal the sequence of secondary images at a fixed viewpoint.
4. Wolfram Research, Champaign, IL 61820–7237 USA, http://www.wolfram.com.
5. BEAM2 ray-trace software, $89 plus shipping. Stellar Software, Berkeley, California, http://www.stellarsoftware.com/.