How a 17-year-old entrepreneur in Poland accidentally made the Apple Watch easier for deaf people

Like a lot of Polish 17-year-olds, Mateusz Mach is into hip-hop. "It is something I identify with," Mach says.  Unlike a lot of Polish 17-year-olds, he decided to turn his appreciation into an app business. After six months of work, he released Five -- a messaging app for Android, iPhone, and Apple Watch that lets you and your friends throw each other custom hand signs, like the kind rappers throw.  It's meant to be quick, easy, and above all, fun. Mach says that his friends using the app use ...