"New York," he said after a brief pause, "is a huge, sprawling metropolis that breeds within itself the seeds of its own destruction. Transportation." I raised an eyebrow. "At best," he went on, "the traffic in Manhattan does not flow--it limps. Let one traffic light fail and vehicles are backed up for several blocks. True?" I nodded. "Yes." "Very well. Imagine, then, a situation where, at one given instant every single traffic light on this congested island turns green and STAYS green." I shuddered at the thought. "Picture the beauty of it," he said. "Not red, which would cause all automobiles to stop, but green, the signal to go! Imagine their mad desire to rush forward in righteous obedience to the law, and their awful frustration to find every other automobile and truck obeying the same law, regardless of the direction from which it is coming. It has been estimated by noted mathematicians who are involved in this plan, that within forty-five seconds all traffic in Manhattan would come to a standstill, it becoming impossible for a car to move forward or backward. Oh, what utter chaos!" "_Ab homine homini periculum quotidianum_," I said. "Eh?" "Man is daily in danger from man. An ancient Roman said that." "He knew what he was talking about. But this is only Phase One of the plan. A corollary is based upon the axiom that one disabled automobile is equal to ten thousand operating ones." "I don't follow." * * * * * "The highways leading into and out of this island. Regardless of the number of lanes, if one automobile breaks down, traffic is immobilized for miles. Multiply that by several dozen, all at the same time, on all the entrances and exits to the island, and no earthly power could untangle that situation in less than a week, if then!" His words evoked an image of metal monsters, stretched as far as the eye could see, steam pouring from their overheated radiators as they raucously bleated for help. "All this can be accomplished quite simply and inexpensively," continued my bearded little man. "However, what of subsurface transportation?" "You mean the subway system?" "Exactly. Once again, simplicity is the key. What do subway riders use to gain entrance through the turnstiles? Tokens. Let us suppose that on this same given day the majority of tokens distributed are all fractionally larger than normal. Not enough to be noticed, mind you, but just enough so they cannot pass through the slots and activate the mechanism." "But--"