Grab some tissues: An adorable dog named Derby, born with deformed front legs, has been given a set of 3-D printed prosthetics. And these custom-made legs, which he can rock back and forth on (to keep him from getting stuck in the dirt) don't just help him walk more easily. With his new legs, he can run.

Derby had the good fortune of being fostered by a woman who knows all about 3-D printing. Tara Anderson works for the company 3D Systems, and she knew that custom prosthetics made with this technology are a more practical choice than traditional prosthetics.