Halo

On another note, related to the latest “light graffiti” subjects coming up, this project has a really good idea for when the battery rans out.
“Halo is a handy light specially dedicated to light-writting. Graffiti artists can conserve their own gesture they have with an aerosol spray. It is possible to change the color and the brightness of the led to change the graffiti’s styles. If the light doesn’t have enough battery, the user must shake it to have energy again.”