Surfaces for writing

Butterfly tattoo
I was driving the car today when I noticed that someone had written 'I wish i had a car' in the dirt on my rear windscreen. They must have done that in mirror-writing for me to be able to read it. It's probably the simplest act of graffiti - the finger that writes on a dirty white van 'also availbale in white' or 'clean me I'm dirty' or, of course, something less polite... in a similar fashion there's writing on steamed up glass... Then, today, I read in Siri Hustvedt about 'dermagraphism' which seems to have become a generic term for a scratch on the skin that appears like a pattern. But in Hustvedt, it's more of a magical act in which passing a hand over the skin reveals a written message - a sort of psychic tattoo. Mmmm!