★★ Indoors was stuffy but the air outside was too thick for its coolness to be any relief. The kindergarteners traipsed out into the gray in their double lines, on assignment to notice things on a loop around the neighborhood. They noticed trash cans and trucks and phone booths, and they noticed when now and then the still-heavy clouds released some drizzle. Their noticing did not rise to the level of complaint, though. Sun was shining on the white tile walls of the stairs at Union Square, and people were casting shadows. The clouds and sun went back and forth; brightness took over a stretch of afternoon, like an underdog basketball team using up its legs in a third-quarter surge, before the gloom claimed its inescapable victory.