As a rule, bionic hands are clunky contraptions made of motors, pneumatics and other machinery that just can't be as elegant as the real thing. Germany's Saarland University might just change that, however. Its researchers have developed an artificial hand that uses smart nitinol (nickel titanium) wires as its muscles. All you do to make them flex is heat them up or cool them down -- the metal 'remembers' its original shape before you bend it, so you don't need bulky equipment to move it back and forth. The wire bundles are as thin as cotton, but they're very strong and can move with much more precision and speed than usual. They don't even need sensors, since electrical resistance in the wires themselves is enough.