The Apple iOS 7 3D illusion of a parallax view—icons seem to float above your home screen—underscores the feeling that the iOS 7 interface is made up of layers.
The most mind-blowing moment of Apple’s iOS 7 video during the keynote was probably the parallax effect that happens when you move your phone: The icons on the home screen stay still while the background image moves slightly underneath them. The effect in Apple’s video is much more pronounced than the one that’s visible in the developer beta. Apple executives told us that the parallax effect is a bit of a work in progress, and it hasn’t yet been decided just how pronounced it will eventually be.
Apple has organized iOS 7 in layers, using the motion sensors in the device to give a real sense of 3D depth. As you move the phone, the layers move in 3D space—you can appreciate the parallax effect, which gives an impressive sense of depth
The OS uses translucency to further enhance the effect, putting things that are not in use behind what the user needs to focus on; when a dialog pops, it does so on its own layer on top of what you were previously looking at. The previous layer recedes back, establishing a clear relationship between the elements being displayed on the screen.