A robotic hand that brings together 3D printing and mechanical engineering offers an affordable prosthetic alternative for patients missing fingers, many of them children, writes John Kosowatz. The RoboHand developed by South African carpenter Richard Van As and Ivan Owen of Bellevue, Wash., originated with Van As, who lost four fingers in a workshop accident. Said Owen, "I had built this silly oversized puppet hand" and put a video of it online. "Rich saw it ... and wanted to collaborate on a design for a partial finger replacement. It was kind of a stream of consciousness effect of the Internet."