There was an exhibition, Day, Light, Night, celebrating the 25th anniversary of Tepta Lighting. They seem to be a company selling (and maybe making, I did not check) lightening equipment. They had some exhibits that it was fun to play with, or just watch. Many changed through time, in intensity and/or colour. This is one of some pictures I took.

The ceiling in a room was lit by small lights that, probably programmed somehow, changed all the time, often in tandem.