The fountain at the southeast corner of the Fourth Avenue Underpass, designed by Kevin Osborn, is a steel grid with cool rippling water flowing over it, surrounded by landscape rock. Was it serendipity, or was it design genius that the rocks are the exact same size and dimension as the steel grid? Whatever it was, passers-by have discovered that the rocks fit perfectly into the steel grid, allowing anyone with a sense of play and a little free time to make grid-based images or text. These anonymous artworks change almost every day. Sometimes there is a happy face or a peace sign; sometimes it's a declaration of love. Every once in a while, there's a surprising picture. Our favorite: a silhouette of the downtown skyline, with the real downtown skyline just behind it.