Optical Illusions Small 320×82 Medium 640×163 Large 1024×262 Download Tiff Original 2400×613 | (238.6 KB) Description Illustration showing optical illusions. It is not always possible to trust the eye to be sure if the lengths of lines a and b are the same. You would need to measure to be sure of your conclusion. Keywords geometry, illusions, lengths, lines, measure, measurement, optical illusion Galleries Visual Illusions Source: C. A. Hart & Daniel D. Feldman Plane And Solid Geometry (New York: American Book Company, 1911) 21
