Geometric Optical Illusions Gallery

by Gianni A. Sarcone and Marie-Jo Waeber

Vision isn't always WYSIWYG
In English, there are 2 essential words to express the faculty and the act of seeing : 1) see, 2) view. The etymological sense of the words see and view are “follow something with the eyes” (from the indo-european seq) and “have learnt” (from the indo-european weid). So, for our ancestors an image is something to shape with the eyes (follow with the eye) and an information taken from the real world (having learnt from this visual perception).

Unfortunately (or fortunately?), seeing isn’t some kind of direct perception of reality. Actually our brain is constantly interpreting and giving structure to the initial visual input from our eyes. If this was not the case, we wouldn’t see colors and we probably would see the world upside down! Another interesting everyday paradox of our vision is that we don’t see the edges of our visual field! In fact, we should see black zones outside of our visual field, but our brain cancels out these zones with a smooth fade-out effect. In the following webpages we have included classic and new optical illusions that will delight children and grown-ups as well as inquisitive minds in search of solid, accessible material on this amazing subject.

The Authors
Gianni A. Sarcone and Marie J. Waeber, designers and writers, are specialists in creative learning. They create and invent educational manipulatives and thinking games which help teach mathematics, visual and plastic arts. Their maxim is: “be curious first!” (click here to get more info about the authors)

The curved grey lines shown in the picture seem
to vibrate and blink forward and backward