Excerpt from a Walt Mossberg Amazon Fire Phone review
"The key to this hope rests with moving beyond the touching and swiping that has become the norm on smartphones since 2007, and allowing users to do a bunch of common tasks, one-handed, by merely tilting the phone. This hands-free navigation is part of what Amazon calls Dynamic Perspective, and it works via a new set of sensors — four specialized cameras on the phone’s face.Amazon’s Smartphone Ambitions Go Beyond Making Shopping Easier | Re/code
The flashiest aspects of Dynamic Perspective involve things like giving images, graphics and games a parallax effect, so static objects seem to move. This is kind of like the way Apple’s icons float over the wallpaper, but it goes much deeper into the user interface and is used more broadly."