One of the little joys of living in my neighbourhood is watching the subway ads get defaced. If it was just a matter of people tagging the ads, I'd consider it vandalism, but the locals have turned it into an art form (I think there are some very creative but underemployed folks in my hood who are quite bored waiting for their morning commute to Manhattan. Perhaps a hint of social deviance as well).
Below is a scene from earlier today. Our local artist carved out the baby's smile and found that it was perfectly overlaid above a row of teeth below. There is an artistry of sorts lurking here.