Rex was instantly hooked. The keyboard was the first thing he wanted to do in the morning, and the thing he wanted to do even when his body couldn't do it anymore, falling asleep. And as his skill at the piano grew, so came other skills. Rex learned to walk, talk and even ski.
But with all his accomplishments, those dexterous little fingers still can't button a button, And real conversation continues to elude him. Emotionally too, Rex is immature.
But not so in his music, says David Pinto, Rex's other piano teacher, who specializes in working with the blind.
Rex is even driven to practice the dreaded scales. But he gets really agitated when he doesn't get something just right. "We need to try this over again," Rex said, visibly irritated at one point.
David thinks Rex's frustration is counter-productive, and has started turning the mistakes into a game. "I deliberately had him go faster and faster, and I said, 'OK, now you're going to make a mistake.' But if you make a mistake, all you have to say is 'No big deal.'"
During an exercise, Rex made a mistake, started to moan, prompting David to take his hands off the piano.
"OK, stop. What are you going to say?" David asked. "No big deal," Rex replied, and completed the exercise perfectly.
David introduced Stahl us to another of his students, 11-year-old Rachel Flowers. Rachel is also blind and a musical prodigy.
David teaches Rachel piano; the flute she is teaching herself.
"She picked up the flute five, six months ago. And now she can play in a nightclub as a jazz flautist. She's just amazing," says David.
And she's improvising. Intellectually, Rachel performs at grade level, but she lags in social skills, focusing almost obsessively on music.
"There is this intriguing triangle of blindness, mental impairment of some kind, and it doesn't have to be the same, and musical genius," Stahl remarks.
"I think that gives us a clue about ourselves. A child who has a limitation has a direct access to parts of themselves that we have in us, but we don't have access to it," replies Pinto.
Sometimes Rachel and Rex play together, and have the musical equivalent of a conversation.
Outside of the music, Rex and Rachel have no interaction. Rex's mother explains her son is not interested in Rachel, the person – just the music. "Maybe down the road, it'll be Rachel the person," she added, laughing.
As Rex and Rachel grow up, will their remarkable talents continue to develop, or will disability at some point get in the way?
A surprising answer can be found in a young man named Derek Paravicini, a brilliant jazz pianist. Twenty-six years old and blind, Derek is even more mentally impaired than Rex.