A common example is the Kanizsa triangle which is induced by three black circles placed in the apexes of a triangle. Each circle has a 60 degree wedge removed so that these wedges become the angles of the illusory triangle

KANIZSA FIGURE: "Kanizsa Figure is a figure that induces the perception of illusory contours defining a shape that appears to be brighter than the background."
Cite this page: N., Pam M.S., "KANIZSA FIGURE," in PsychologyDictionary.org, May 11, 2013, https://psychologydictionary.org/kanizsa-figure/ (accessed January 23, 2021).