Let me introduce you to Derby, a sociable and adorable doggie who got a chance at a normal life. Derby was born with very small forelegs and no front paws, which made it impossible for him to walk and sit like a normal dog. Fortunately, Derby was adopted by a kind-hearted woman who made it possible for him to get a pair of new custom prosthetic legs. The dog progressively learned how to walk on prosthetics. I think it’s safe to say Derby has made some significant progress, as he is now fully able to run using his 3D printed prosthetic legs and sit like a real dog.