The other day we stopped by an orthotics and prosthetics office called Hangar. This gentleman was nice enough to show us how some of the equipment works as he explained to us the many types of prosthetic devices they could produce.
In this image, he had scanned Zach's hand with a device. The computer could read Zach's hand and sent an image to the computer that could be turned and rotated in any direction. It was pretty amazing.
I also took a video of him testing an electronic device on Lily's leg. You can see how it causes her lef to move uncontrollaby.