Mildred Howard's installation "Three Shades of Blue"...
is found at the Fillmore Street Bridge, at the intersection of Geary and lower Fillmore Sts. "Two sets of colored and etched glass windscreens consisting of 20 panels of glass, approximately 5 x 8' each" (from the SFAC Public Art website.)
Based on a poem by Quincy Troupe, the piece evokes images of Fillmore's dynamic meeting/overlap/clash/mash-up of Japanese/Jewish/African-American/Jazz/Beat cultures and politics. (Read a short history of Fillmore here. Its very interesting; I had no idea how culture-rich this area was and is.)
Upon not-so-close inspection, you can see the installation has been vandalized: "It's been scratched. It's been shot." And graffitied. I thought the spiderwebbed glass was intentional at first. I believe I read something awhile ago about how the city is considering relocating it to avoid further damage.