Editing Reflection (physics) (section)

=== Multiple reflections ===
[[Image:MultipleReflections60Degrees.svg|right|thumb|upright|Multiple reflections in two plane mirrors at a 60° angle]]
When light reflects off a [[mirror]], one image appears. Two mirrors placed exactly face to face give the appearance of an infinite number of images along a straight line. The multiple images seen between two mirrors that sit at an angle to each other lie over a circle.<ref>{{cite journal|title= Virtual mirrors |journal= Physics Teacher|volume=20|page=278|year=1982| author= M. Iona |bibcode = 1982PhTea..20..278G |doi = 10.1119/1.2341067|issue= 5 }}</ref> The center of that circle is located at the imaginary intersection of the mirrors. A square of four mirrors placed face to face give the appearance of an infinite number of images arranged in a plane. The multiple images seen between four mirrors assembling a pyramid, in which each pair of mirrors sits an angle to each other, lie over a sphere. If the base of the pyramid is rectangle shaped, the images spread over a section of a [[torus]].<ref>{{cite journal|title=Output irradiance of tapered lightpipes|journal=JOSA A|volume=27|issue=9|year=2010|url=http://fisica.uaz.edu.mx/~imoreno/Publicaciones/JOSA2010.pdf|doi=10.1364/JOSAA.27.001985|author=I. Moreno|pages=1985–1993|bibcode=2010JOSAA..27.1985M|pmid=20808406|s2cid=5844431|access-date=2011-09-03|archive-date=2012-03-31|archive-url=https://web.archive.org/web/20120331162520/http://fisica.uaz.edu.mx/~imoreno/Publicaciones/JOSA2010.pdf|url-status=dead}}</ref>

Note that these are theoretical ideals, requiring perfect alignment of perfectly smooth, perfectly flat perfect reflectors that absorb none of the light. In practice, these situations can only be approached but not achieved because the effects of any surface imperfections in the reflectors propagate and magnify, absorption gradually extinguishes the image, and any observing equipment (biological or technological) will interfere.