Public Service Announcements are held to a different standard than other commercials. One of their biggest challenges is to get people to keep watching. Another is not to be lame. This one, for a British homelessness organization, unspools slowly. It takes a moment for the viewer to realize what is happening and to cotton to the visual trick. For many people, their homes are just like a house of cards; one slip and suddenly the whole enterprise flutters away. Cinematically stylish, with its muted palette and rough camera work, the commercial's tone evokes less pity than shock, which seems more likely to spur action. The Radiohead sound track doesn't hurt either.