Grey.

Had a swift look into Middlesbrough this morning, this is the huge piece of chrome art in the centre of town, it has a series of lights on it that when you text a certain number to it, it changes colour. When it was first erected it blew a gasket in the first hour with way too many texts, these days I think locals try to change the lights not through texting but through the technology of hurled rocks. Nice idea though.