80 years after Ub’s invention, the multiplane is alive in iOS 7. Previous versions of iOS were built on a single plane with raised and textured areas on that surface, like a topographical map except with buttons instead of mountains. iOS 7 is instead designed with multiple flat layers. Each level is strikingly flat, but by layering two or three, spaced apart, Apple has achieved an overall sense of depth.
See also: Walt Disney explaning and demonstrating the multiplane camera.