The visitor switches a video signal from a camera pointed at themselves, between a 1 kilometer coax cable link and a 1 kilometer fibre optic link. They discover how much better the signal through a fibre optic cable is. Furthermore an air gap is created in the fibre link and the visitor can block the signal by placing their hand in the way. A supporting display shows how the light beam bounces down the optic cable by reflecting off the inside walls.