6 amazing optical illusions

In the April 1971 issue of New Scientist magazine, Allan Neil present his new type of optical illusion…

Full scale research has not yet begun on the information-processing mechanisms which respond to the subtle factors in these illusions, but the preliminary studies have not overestimated their importance.

Here are 6 examples of these truly remarkable illusions…

Amazing, huh?

(via Ironic Sans, Lemon Harangue Pie)