In one of the most iconic scenes in science-fiction films, Luke Skywalker casually examines his new synthetic forearm and hand. The Star Wars hero is able to move the fingers by extending and contracting pistons shown through an open flap along the wrist. Then he senses the robotic surgeon's pinprick of one of the fingers. Not only can the prosthesis be moved with Skywalker's thoughts, it feels to him like his own hand.