OMG, I'm still at work but I made a picture with my cellphone this afternoon. Don't know yet how to transfer it to my PC. I still have 7,5 hours to find that out
In New York, graffiti is an embarrassment of riches so it is easy to get overwhelmed by all the writings on the wall. So may I offer a mini-gallery to share this wealth:
After seeing Tim's excellent shot of Maori rock carving (http://www.pbase.com/tvw/image/88257982) I felt pretty stupid not thinking of prehistoric graffiti when it's almost in my backyard!
The exact age of this work is uncertain... but it is pre-contact and most likely more than 400 yrs old.