s soon as I got out the door of Northwestern Station, I heard an alto sax. A strange riff repeated four times followed each time by a quieter passage; then a slightly different riff a fifth above the first, repeated twice. Back to the first riff. Some of the echoes from the buildings around us made the riffs sound slightly out of phase with themselves, sounding a little sad, ironic, jerky, strange. The man playing it was wearing a navy blue pea coat and a tam that looked like a beret. Half a block after passing him, I finally realized he was playing a bebop version of “Pop Goes the Weasel.”

I noticed the smile first: a private smile, unusual for walking the streets of the Loop during the evening rush hour. She was carrying a bunch of flowers wrapped in a cone of plastic film, and a small balloon. Blue blazer, about thirty. A good-bye party? A promotion?

Near the Art Institute, a young white woman unconsciously averted her eyes as she passed nine black women walking together. Two different cultures. The white woman walked quickly, dressed in conservative chinos and wearing no makeup, alone and self-contained. The black women walked slowly, dressed in going-out-to-dinner clothes, trading jokes and loud conversation.

Veterans with their American Legion caps accepting donations for veteran’s hospitals outside Union Station. They looked out of place among the hurrying throngs of well-dressed mostly young or middle-aged people streaming towards the station. Neither I nor anyone else seemed to stop for them.