HoloPhone Flat
From Tardis Wiki, the free Doctor Who reference
A HoloPhone Flat was a phone made from a sheet of near-indestructible glass that used nanotechnology to "create the illusion of applications and circuitry". Chris Cwej remembered that he'd first seen one from his universe from 2020.
When Chris arrived on another Earth in Dawn 1027, he found a HoloPhone Flat in the pocket of a Cwejen he was currently inhabiting. He used it to jot down information given by the President. (PROSE: A Bright White Crack)