Artists have been using recycled materials ever since Marcel Duchamp took a urinal, turned it upside down and dubbed it "Fountain" nearly a hundred years ago. But lately the cause has gained a new urgency. Highlighting this trend was Alchemy, at the William Havu Gallery, in which three artists used non-art materials to create their work. Coloradan Stan Meyer wove roofing tar paper into wall hung constructions. Ann Weber, a California artist who is also into weaving, used old pieces of cardboard cut into strips to make freestanding sculptures, some of them quite large. Finally, Marta Thoma, also from California, strung up old bottles to turn them into suspension sculptures. There's no LEED certification for artwork, as there is for buildings, but if there were, Meyer, Weber and Thoma would obviously qualify.