PHENOMENOLOGY OF Perception

British neuroscientist, Anil Seth, tells us our brain takes a "best guess" approach to interpreting sensory data. So we don't necessarily see things as they are, but are influenced by our past experiences, expectations, beliefs, as well as cultural factors. 

Below are three images of the same painting, Luminous, rotated 90 and 180 degrees. Notice how the concave shadowy forms in the first image appear to change going from convex to concave (or vice-versa). At the 90 Degree rotation the forms appear to switch from one state to the other in a permanent loop.