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'(<a href="http://www.j-archive.com/media/2008-09-23_DJ_11.wmv">Cheryl of the Clue Crew waves a reflective stick through a projected image.</a>)  Even when a projected image appears to be gone, you can still see it when I wave this stick because of this phenomenon in which the light detectors in the eye send signals to the brain'
the persistence of vision