" All that barbed wire, concrete barriers, checkpoints. You shut the city down. You stopped it flowing—put it on life support. You stopped people getting around to do what they had to do. You cut the violence, sure, but you did it by killing the city.” “All right,” I said, “you’re so smart, how would you have done it?” And Steve pointed out what every police officer, paramedic, traffic engineer, and social worker knows, and what should have been obvious to me all along: a city is a living organism that flows and breathes, and any public safety solution that no longer lets it flow is no solution at all. "

― David Kilcullen , Out of the Mountains: The Coming Age of the Urban Guerrilla