Stare at the center of this figure.  Does it appear that there is scintillating activity (or movement) within the purple rings? This figure, titled “The Enigma”, was painted by Isia Leviant in 1981.

Presented below is a series of black squares.  Do you notice anything peculiar about this pattern? As your eyes scan this matrix, do you see dark phantom dots appear in the white intersections?  This illusion was proposed by Ludimar Hermann in 1870.  As such, it is referred to as the Hermann grid illusion.