The typical prosthetic arm or hand once cost many, many thousands of dollars, but a group is now dedicated to providing the technology - via 3D printing and a worldwide design community - at a fraction of the cost. E-Nable is responsible for a growing list of adults and children who now have affordable prosthetic arms and hands, and their latest project was aimed at helping a little boy in England, Charlie Egan, get a working device to make him a sort of 'superhero' in the eyes of those around him. You can read all about Charlie and E-Nable here: http://3dprint.com/33720/3d-printing-superhero-arm/