Tynan P, Sekular R
Science. 1975 May 30;188(4191):951-2. doi: 10.1126/science.1138365.
Moving contours surrounding an empty region make phantoms appear to move through the empty region. The phantoms are contours, dimmer than the inducing contours but of the same pattern, color, speed, and direction of movement. The phantoms originate in the brain and may be related to completion effects most often seen with visual pathology.