Oscar Reutersvärd was a Swedish graphic artist who in 1934 pioneered the art of 3D drawings that may initially appear feasible, yet cannot be physically constructed.

The illusion plays on the human eye’s interpretation of two-dimensional pictures as three-dimensional objects. Visual perspective is twisted and used to create the illusion of a three dimensional object that cannot possibly exist. The problem arises because the viewer assumes that the features of the figure that are touching in the two dimensional representation are at the same distance from the viewer. The use of perspective to create depth adds to the effect of the illusion.