As a kid growing up in poverty in rural Bolivia, Roly Mamani built his own toys. Now a 34-year-old engineer, he 3D prints limbs for Indigenous compatriots scarred by life-changing accidents. One of their beneficiaries is 59-year-old Pablo Matha, who lost his vision and right hand seven years ago in a mining accident involving dynamite. Matha says the prosthesis "is a great gift." He now plays the guitar to earn a living.