“Always look up” they say, but in Ann Arbor, you should always LOOK DOWN, so you don’t miss a chance encounter with Nadine the Mouse or another of artist David Zinn’s familiar characters who turn sidewalk imperfections into art. David Zinn's new book, "Chance Encounters," launches this month. He stops in for a catch-up with Deb Polich of Creative Washtenaw and host of "creative:impact."