There is virtually no limit to what you can decorate with color-changing tiles (from Inventables). Daytime cityscapes turn into urban night scenes as the temperature in a room shifts. Notable applications include showers, floors and others surfaces likely to be exposed to temperature variations over time.
While some of these are simply colored and relatively inexpensive there are all kinds of untapped design potentials yet to be explored. Perhaps they would make a good interior design match for an exterior application of some light transmitting concrete.