Andy Goldsworthy makes beautiful, ephemeral things out of leaves, twigs, roots, stones, and the like. The web site gives you a taste, but better are the books and videos of his work. It's only an inference, but I think I've twice stumbled over anonymous Goldsworthy-inspired urban works: once I encountered a fan of autumn leaves arranged on a wet sidewalk with perfectly graduated colors, and once in a disused, weedy tennis court I found a circle in the weeds with a twig-and-leaf sailboat sailing on a pebbly sea. A special, secret kind of pleasure and pain grew from revisiting the little boat and watching it crumble away.