There's only so much you can do with two arms and hands. That's basic science. But what if you could add extras without the need for ethically shady surgery or trading your apartment for a hovel in the shadow of a nuclear power plant? That's what researchers from Keio University and the University of Tokyo hope to achieve with their "Metalimbs" project. As the name suggests, Metalimbs are a pair of metal, robotic arms that doubles the amount of torso-extremities and worn with a backpack of sorts. And unlike thought-powered prosthetics we've seen recently, these are controlled not with your brain, but your existing limbs. Specifically, your legs and feet.