It works like this: several cameras allow the robot to see what is coming its way, and based on its "experience" the arm's onboard computer produces a mathematical model to represent the objects course. The bot then changes position extremely quickly--it can move positions in five hundredths of a second, according to an EPFL release--and uses its "experience" to decide where to grasp the object. Scientists have trained it to catch all the things you see in the video, plus a ball and a hammer(!).