Lumen-Illusion is one of several viewer interactive, luminous sculptures created by Christian Schiess. This piece utilizes sixty 24 inch electric gas discharge tubes, which flash computer controlled patterns that are either preset or manually arranged to demonstrate the phenomena of apparent motion. The colored lights in this exhibit look like they are moving in different patterns, but it’s all an illusion. Your visual system tries to make sense of these flashing lights by piecing together the stationary images to create an illusion of motion, called apparent motion.