The Oppel-Kundt Illusion is an optical illusion that was first described by German physicist Gustav Theodor Fechner in 1876. It is an illusion of motion created by two parallel lines of alternating black and white stripes. When the stripes are viewed from a distance, they appear
The Oppel–Kundt illusion is a geometric optical illusion that occurs when comparing the sizes of filled and unfilled parts of the image. The illusion is named after German physicists Johann Joseph Oppel and August Kundt. It is also known as the "filled-space illusion" or the "illusion of interrupted extent". Depending on the filling elements used, there is a wide variety of graphic implementations of the Oppel–Kundt illusion, which also differ in the magnitude of the visual distortion effects they cause.