Rising object illusion

Abstract

The geometric principle of a new 3D optical illusion, which we refer to as the ‘rising object illusion,’ is presented. In this illusion, a horizontally lying columnar object rises vertically in a mirror, although the mirror stands vertically, and consequently the horizontal directions in the real world remain horizontal in the mirror. Actually, the illusion object is a picture of the original columnar object expanded by 1.41 (square root of two) in the direction of the axis and placed horizontally. This visual effect occurs only when the axis of the object is directed toward the viewer, and the viewer sees the object with a -downward orientation. GRAPHICAL ABSTRACT