Dawson Riverman’s parents tried to help him make the best of it.

Born without fingers on his left hand, Dawson struggled to perform even the simplest tasks, like tying his shoes or holding a ball. “God made you special in this way,” his parents told him. But by age 5, Dawson was demanding tearfully to know why.

The Rivermans, of Forest Grove, Ore., could not afford a high-tech prosthetic hand for their son, and in any event they are rarely made for children. Then help arrived in the guise of a stranger with a three-dimensional printer.

He made a prosthetic hand for Dawson, in cobalt blue and black, and it did not cost his family a thing. Now the 13-year-old can ride a bike and hold a baseball bat. He hopes to play goalkeeper on his soccer team.