O4 Ames Room with Birgit and Ingrid Brill 1.jpg
O4 Ames Room with Ingrid and Birgit Brill 2.jpg
O4 Art Work with Distorted Perspective.jpg
O4 Cartoon B.C. Railroad Track Illusion.jpg
O4 Cartoon CLOSE TO HOME M. C. Escher as a Child.jpg
O4 Escher Spiral Staircase Illusion.jpg
O4 Impossible Waterfall Escher.jpg
O4 Impossible Waterfall Three Dimensional Model 1 with Builder.jpg
O4 Impossible Waterfall Three Dimensional Model 1.jpg
O4 Opposites Optical-Illusion.gif
O4 Photograph Railroad Track Illusion.jpg
O4 Three Dimensional Quilt.jpg