Dynamic Perspective adds a new dimension to Fire Phone's UI

Amazon is using 3D to add a new dimension to using and interacting with its newly unveiled Fire Phone. The Fire Phone uses all of its sensors to give users a new perspective in interactions. Fire Phone uses its four front-facing cameras that are mounted on the corners of your screen to track your face and the phone's movement to generate the the dynamic perspective. This allows for gentle tilting to flip pages on Kindle Books or zoom in on images depending on direction and angle of tilt.

source: androidcentral