Robotics whiz envisions prosthetic limbs for all

A high school teacher in a black coat enters the classroom. "Good morning," he says to the students before starting his lecture, with his right hand busily scribbling something on a blackboard and his left holding a physics textbook. Then, while holding the chalk and the textbook, he points at a female student and asks a question. "OK, that's correct," he says, giving her the OK sign with his third hand. The 28-second YouTube video titled "Three-handed Sensei" (jtim.es/OFd530aIiZV),