You certainly have seen the play by now—you would have had to go out of your way to avoid seeing it. It was late in the first half of Sunday’s Chiefs-Ravens game, a second-and-1. Patrick Mahomes zigged to the left, then zagged back to the right, evading the rush as he scanned the field. Then, with his head pointed squarely downfield, he slung the ball across his body, firing it diagonally across the hash marks and painted field numbers to his left. Receiver Demarcus Robinson, crossing the field, made the catch at a spot where Mahomes had given zero outward indication he was going to throw.