Sam moved forward and reached for the young man’s forearms. He hoped to subdue him quickly without any fighting and escort him from the playground; there was no point in provoking a riot. The tormenter, all slum muscle and grace, recoiled; Sam had barely touched him. The playground instructor saw the white arms and dirtied fists spring into position; a second later it was as if someone had exploded an electric light-bulb in his face. He was stumbling backward on his heel, feeling a thousand needles stinging his offended chin. Numbness radiated through his teeth and cheeks, and a little bath of salty blood was forming inside his lower lip. he had not fallen, however, and as his head cleared he saw the gatecrasher bouncing professionally, fists in the classic boxer’s pose, the abysmal face aglow with hoodlum joy.