Basem Fathi, an organizer of Monday’s protests in Cairo, was scrambling around the capital, trying to buy towels and tents. On a day in which tens of thousands of people thronged the streets in the type of large-scale protests that authoritarian Egypt hasn’t seen in decades, demonstrators had occupied the central Tahrir Square, where they had the parliament building surrounded. Now they looked ready to stay the night. Fathi seemed taken aback by the success. “We didn’t have a boss for this, but the heads of the protest are trying to supply some logistics,” he said.