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.

I found a similar picture at the website of the firm. I think they can be proud.