Pictured above is a particularly wrecked up tile. There are more photos available on my mom's flickr set, and in particular I think it's fascinating how the older tiles seem to have decayed. Here's one that's a little bit more intact:
This one's missing the paragraph at the bottom but it's completely together as if it was meant to be there. That's what's so striking about them: they fit in perfectly but they're so alien. Walking around downtown Saint Louis you might never notice them, but your eyes glance downward and you see that what you thought was just random schmutz on the pavement is actually this colourful tile full of bizarre nonsensical rhetoric.
They are all placed in such busy places though, which is the most frustrating thing about the whole affair for me. The only one I could find in Chicago was in one of the busiest areas of Chicago—at least as far as foot traffic goes. So not only does this mean that whoever placed these tiles had ninja-like powers of invisibility, but it also means they are very difficult to examine in much detail. They're all in the middle of the street, usually on crosswalks, typically visible easily from the curb, but I've still never really been able to get really close to one. Partly that's because I'm not really into squatting down and closely examining parts of crosswalks while I'm supposed to be walking across them.
I took photos of my own which are available on my flickr page, too. More info here or on my flickr page as I look at the photos some more.
Stay curious, space cadets.