A man shuffles cards across from me on the shuttle train. It’s an unusual activity to see on a train, and the fact that he’s sitting directly across from me makes him impossible to ignore. He’s a thin, twitchy Caucasian man with a buzzcut and tattoos. I soon realize that his shuffling is anything but an idle pastime: he’s practicing a very specific maneuver, which involves spreading and dividing the deck into four equal sections clasped delicately between his fingers, which he then manipulates in such a way that the four sections are flipped over one another in a kind of round-robin pattern before being reassembled into the deck. The maneuver – whether it’s part of a standard card trick or a flourish of his own invention – is mesmerizing, and by the end of the train ride I’ve become familiar with his struggle for mastery to such an extent that I can predict the parts where he’ll fumble and those where he sails through without a hitch. He’s completely absorbed in his practice, and shows no signs of being aware that he has an audience of (at least) one. Several days later I’m passing through the 23rd Street station on the 6 line and I’m astonished to see the same man sitting on a bench in the station. He shows no signs of getting up when the train arrives – he’s too absorbed practicing his card trick.