The 3rd arm was created by myself and William Fisher in our first year at Oxford Brookes. It was created from an old lamp, science lab clamp and a few bits of metal we found laying about. We made a harness which sat comfortably around the shoulders and chest. We also sewed a third arm to a jumper giving us a fashionable style whilst we wear the equipment.The idea was to have a spare hand to hold something whilst the other two (the real ones) were busy with something else. That's pretty much it really.