Spinnning tens of thousands times a second, four rotors cut through the air with their propellors. Their motion lifts them in unison, for they are connected together. In the center of the apparatus sits a bank of sensors, processors, and a radio acting in concert to control the great flow of air passing over it. Some ways away, perhaps near, perhaps far, its pilot watches over it. Whether by program or controller, they hold the fate of the airborne being in their hands. Quadcopters are fascin...
