Ah, where was he in the hippy days of the ‘60s? Designer Jonas Samson has a hit in his light-emitting wallpaper.
As long as the wallpaper is turned ‘off,’ it is indistinguishable as a source of light. Instead, it is just what it appears to be: wallpaper.
Samson demonstrates how it is possible to use a 2D flat surface as a light source instead of a 3D object.