You know those asphalt tiles along Smithfield Avenue in downtown Pittsburgh? These ones?
Ever wonder who did that? And how they’re made?
Well, we can’t answer the first question. But we can answer the second!
Some DIY folks have posted a neat little article with their story of how they stumbled across the Pittsburgh tiles, how the artist made them, and how you can too. (Originally from Recipies for Disaster: the anarchists cookbook.)
And it’s one of the most popular articles on the site.
yeah, they're found all over. the local people in your link are friends of mine. google: toynbee plaques.
they're all over the country – here's a (poorply updated) list of their appearances – http://www.toynbee.net/