Seattle artist Mandy Greer spent three months creating a 200-foot fiber river of brilliant blue yarn and recycled fabric for her public art installation Mater Matrix Mother and Medium. The city-commissioned piece is supposed to get Seattleites thinking about environmental stewardship and our urban watersheds. Greer has been holding crochet-a-thons in coffee shops, festivals, parks, and libraries throughout Seattle since May. The results are now woven through the woods. Her prodigious blue textile spider webs climb and slink around the trees, creating a calming and somewhat spooky atmosphere. Tonight, Greer collaborates with local modern-dance choreographer Zoe Scofield in a performance that will celebrate mythical power of water. CHANTAL ANDERSON

Thu., July 16, 6:30 p.m.; July 17-Aug. 23, 10 a.m.-6 p.m., 2009