Every once in a while, I come across a sculpture that makes me go, "Oh. Wow." This is one of them. It's a coral reef that artist and ocean advocate Courtney Mattison crafted out of ceramic. The monumental wall piece, called Our Changing Seas III, is the third in Courtney's series of large-scale installations "inspired by the fragile beauty of reefs and the human-caused threats they face." On view till August 28 at the Palo Alto Art Center.