 Troxler's fading, discovered by Troxler in 1804, is a very similar phenomenon in which an object away from one's focus of attention disappears and reappears irregularly.There is no necessity for a moving background for this illusion to occur.Other similar phenomena in which salient stimuli disappear and reappear include binocular rivalry, discovered as early as 1593, monocular rivalry, and flash suppression.