A 64-year-old man runs a Saturday chess club for children in a back room he long ago christened the Looking-Glass, after the enormous foxed mirror nobody has ever managed to take off the back wall. Halfway through a game this morning he stopped, put a hand flat on the table, and asked one of the parents to take over. His heart, he says, is going fast and completely regular — like a drum roll that will not slow down. The parent called an ambulance.