ART: After purchasing a crane truck to use as a ladder, laboring nine months and welding 500 pounds of metal, Bruce Fox completed his “Knølhval” (Norwegian for humpback) in March on the Point Reyes Station mesa. The 13.5-foot steel sculpture, which spins in the wind, was Mr. Fox’s answer to a request from his partner, artist Shirley Salzman, to put something on her leach field.