Optical Illusions Small 320×160 Medium 640×319 Large 1024×511 Download Tiff Original 2400×1197 | (392.2 KB) Description Illustration showing optical illusions. It is not always possible to trust the eye to be sure if the lines are the same distance apart. You may 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
