Necker Cube Illusions

The Necker cube is an optical illusion named after Swiss crystallographer Louis Albert Necker (1832) which consists of a two dimensional representation of a three dimensional wire frame cube. 

It is an ambiguous figure in that it can be interpreted as having the front of the box facing downward or facing upward. This is due to the way in which the cube is drawn. When the edge lines cross, the picture does not show which is in front and which is behind. This ambiguity allows the viewer to interpret the cube's orientation either way. When staring at the image it may flip back and forth between these two orientations. 

Image Credit Alec Nevala-Lee

The version below is an interesting variation which is easily seen as a 2 dimensional figure as well as a 3 dimensional figure with two interpretations.

Illusions Index: Necker Cube
The Eye's Mind

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