The blast echoed from somewhere near the front lines. A fragment -- probably a shotgun pellet -- ricocheted into Muhammad Abdel Aziz's face. He flinched and touched his cheek -- no wound, this time. Earlier, three or four had gashed his chin and swelled one side of his jaw, spattering his striped shirt with blood.
Shouts, explosions and gunfire echoed from all around the glass-carpeted streets. In an alley, Abdel Aziz found shelter from the chaos that had engulfed the neighborhood surrounding Egypt's presidential palace. He had come to protest against President Mohamed Morsi and was treated in a field clinic -- a café on normal days -- after being shot.