Three Trees In Front of San Francisco City Hall Have Been Yarn Bombed With Adorable Giraffes A post shared by Lorna & Jill Watt ( on Sep 2017 at PDT Sisters Jill Watt and Lorna Watt who have yarn-bombed much of the San Graffiti Kunst, Urban Graffiti, Graffiti Designs, Garden Art, Garden Crafts, Garden Design, Yarn Bombing, Guerilla Knitting, Crochet Tree