Architect Rose McNulty, of Asian Neighborhood Design, was tasked by the SF Housing Authority with carrying out security-related upgrades to the four large buildings of Chinatown's Ping Yuen public housing complex.  Her ingenious allocation of funds permitted the commissioning of one hundred mosaic panels (and three larger multi-panel works for the exterior of the buildings), each using at least 50% mirror, to incorporate stairwell artwork that doubles as improved security visibility for residents.  The artwork also enables place-finding  in the eight-story buildings, with nature themes beginning on the ocean floor and ascending through river and stream fauna to flying insects, butterflies, birds, and culminating with sun, moon and stars on the uppermost levels.  The tight time frame on this project called for the involvement of many hands, so student interns trained in mosaic technique participated in fabricating the panels.