Great post here on Light Graffiti.
Image Source: Colour Lovers
“A number of graffiti artists have been tagging everything thought to be impossible without being caught. Well — it’s actually not illegal for them. They’re not using paint. As it turns out, time-lapse photography isn’t just for blooming flowers, skyscapes, or brake lights anymore. Termed Light Graffiti, tag artists are taking their colour to an all new level.”