Pioneers in 3D printing are always looking for ways that it can be used to make life better or easier for the rest of us. One innovation is to recreate a realistic but artificial human body, or a partial body, as an exact copy of a particular surgical patient. A medical scanner maps out the size, shape, and positions of organs, and then a copy is manufactured, as demonstrated here by the company Lazarus 3D. That's for surgeons to practice on, to avoid that moment when they cut a person open and find surprises. It's a sort of dress rehearsal for the actual surgery. The robotic surgery part is not really crucial to the rest of the story, but it's pretty neat anyway. Tom Scott volunteered his body for the demonstration, and the scan revealed he luckily didn't need surgery, so they added a cyst just so we could watch them remove it.