In physics, the accordion effect (also known as the slinky effect, concertina effect, elastic band effect, and string instability) occurs when fluctuations in the motion of a traveling body cause disruptions in the flow of elements following it. This can happen in road traffic, foot marching, bicycle and motor racing, and, in general, to processes in a pipeline. These are examples of nonlinear processes. The accordion effect generally decreases the throughput of the system in which it occurs.