(The New York Times) – The teenage students were lowered into a mass grave one after another, shoulder to shoulder — just as they had sat at their lecture hall the day before. A suicide bomber, perhaps no older than they, had walked in as their algebra class ended and physics was about to begin, detonating his explosive vest and turning the university prep center into a scene of carnage. On the whiteboard, basic algebraic equations were covered in blood. A nearby blackboard, where “Valentine day” was written in faded chalk, was riddled with holes from the ball bearings that were packed into the bomber’s vest.