Three years ago, Paul McCarthy began searching for an inexpensive yet functional prosthetic hand for his son Leon, who was born without fingers on one of his hands. After coming across a video online with detailed instructions on how to use a 3D printer to specifically create prosthetic hands, he had a brilliant idea. This dad decided to create a custom hand that would eventually help his son with little things we normally take for granted, like picking up a water bottle or riding a bike. (Source: CBS Evening News) A normal prosthesis would have cost the family in upwards...