(3 quadrocopters = 12 rotors) To toss the ball, the
quadrocopters accelerate rapidly outward to stretch the net
tight between them and launch the ball up. Notice in the video
that the quadrocopters are then pulled forcefully inward by the
tension in the elastic net, and must rapidly stabilize in order
to avoid a collision. Once recovered, the quadrotors
cooperatively position the net below the ball in order to catch
it. Because they are coupled to each other by the net, the
quadrocopters experience complex forces that push the vehicles
to the limits of their dynamic capabilities.