Light painting. I attached an led light by a string from the ceiling in my basement. I swung the light around while I took a photo from underneath in bulb mode. About 20 sec exposure. Half way into it I covered the lens with a black cardboard ( shutter was still going) and replaced the light with a different color led and swing it again. Uncovered the lens and let it record the second color . About an other 15 sec or so.