Toynbee Tiles

A recent article on the Kansas City Star's web site brought the phenomenon of Toynbee Tiles to my attention. If you have not yet heard of this intriguing global mystery, take some time to explore it. This is a picture a friend and I took of one of the two such tiles in downtown St. Louis. The text in the red border at the bottom reads, "You must make + glue tiles. ¡¡You!! You must make + glue tiles!". Yeah, I know... I'm working on it.