You know that moment when you’re walking with someone, say on a hike through the woods or on a wide downtown sidewalk, when your footsteps fall into a paired rhythm? Maybe you were talking for a while and got quiet right before it happened, or maybe the sun went behind a cloud and a cool breeze kind of floated around two pairs of sweaty arms and legs. Maybe a hawk circled above, its shadow spilling over your path. You have to walk a little ways at first, it doesn’t happen right away. And you don’t even notice that you’re walking in perfect syncopation until you’ve been doing it for a while. Someone always breaks the spell by saying, “Oh! We’re walking in time with one another! Did you notice?” The other person says, “Oh yes, we are!” Then they stop, and then you stop, and the heartbeat steps are scattered.