This isn't a new device, however. Instead, it's a photography-focused app called Reflexion. OnePlus releasing an app may be surprising enough, but perhaps more so is the fact that it's available for both Android and iOS. And of course, on Android, it's not limited to OnePlus devices, so anyone can use it.
The video above probably best summarizes what Reflexion is all about. It's a simple app that creates images that are made out of four parts, two of which are reflections of the other two. OnePlus says Reflexion lets you explore "contrasts and harmony in everyday moments", as well as "capture your world, express your unique personality and share it with those you care about".
It uses both the rear and the front camera on your phone, each of them capturing one image. These are then transformed by the app into the four component bits of a Reflexion image.