A long-awaited boost in iPad sales may have been news this week to Apple investors, but it was no surprise to Marty McDonough, who develops apps for the company's mobile platform, iOS.
McDonough says his latest project was not only built for Apple's tablet computer, but that its very existence was inspired by the high-end iPad Pro.
"When I saw what the pencil and the iPad Pro could do, I said, 'That's cool, I need to build something'" that takes advantage of the product's digital stylus, McDonough, 37, told CNBC. "It was definitely the inspiration."
The resulting program, called ShadowDraw, teaches users how to draw by mimicking -- step-by-step -- the style and hand strokes of famous artists.
"It's like karaoke for drawing," McDonough says of the app, which will be available later this year.
One of his previous apps, an automated language tool called Odyssey Translator, has been downloaded more than 3.5 million times from the AppStore since he created it in 2009.
McDonough's drive to create another iOS-based app shows how Apple's ability to innovate has inspired its army of outside developers to keep making compelling software for its products.
It also helps explain iPad resurgence in the second quarter -- unit sales were up 15 percent from a year earlier to 11.4 million units. It was the first year-over-year sales rise for the product in three years, and part of better-than-expected quarterly results that helped drive Apple shares to a record high.
Personal tragedy leads him to write software
Yet Apple's innovation and the potential rewards it offers aren't the only things that drive McDonough.
When he was nine years old, he survived an automobile accident that paralyzed his mother and killed his younger brother.
That traumatic event, which also injured his father but left Marty and his baby sister unhurt, helped shape his future as a software developer. In particular, helping to care for his wheelchair-bound mother shaped the kind of applications he's built.
"Every day of my youth, every building, path and product (that his mom had to use) was a new obstacle, one I needed to innovate and problem-solve," he says. "I want to make things more accessible to more people," he says.
McDonough is particularly excited about his latest software because it's more than a drawing tool. Stroke survivors can use it to rehabilitate their hands and children with attention-deficit disorders can use it to focus better, he says.
"I watched my mother learn to write again with atrophied hands," says McDonough. "Making apps has given me an outlet to build solutions that can potentially help a lot of people."
ShadowDraw has already received plaudits from professional artists.
"The best educational feature to me of ShadowDraw is not just seeing the artist's final drawing, but actually getting to understand how they got there," says Andrew Robinson, a comic-book artist who's drawn for Marvel and DC Comics, in a video in support of ShadowDraw.
The program is set for release in the App Store this fall and will be compatible with the latest version of Apple's mobile operating system, iOS 11, according to McDonough.
The app itself will be free, McDonough says, but users will pay "a low monthly price" to access famous works of art to draw. They can also pay a fee for tutorials by well-known artists.
McDonough says part of the reason for his success at building apps is his ability to "drill down on the user experience" and find a way to improve it.
"I do what I do because I want to make hard things easier," he says.