optical illusion

3D Schröder Staircase

Schröder stairs is an optical illusion of a set of stairs which may be perceived either as leading from left to right downwards or the same staircase only turned upside down.

Schroeder stairs

Mathematician Kokichi Sugihara took the Schröder staircase concept, figured out how to make it in 3D, and won the Neural Correlate Society’s Illusion of the Year Award for 2020.

(via Coolhunting)