  Periodic forcing of nonlinear oscillators generates a rich and complex
variety of behaviors, ranging from regular to chaotic behavior. In this work we
seek to control, i.e., either suppress or generate, the chaotic behavior of a
classical reference example in books or introductory articles, the Duffing
oscillator. For this purpose, we propose an elegant strategy consisting of
simply adjusting the shape of the time-dependent forcing. The efficiency of the
proposed strategy is shown analytically, numerically and experimentally. In
addition due to its simplicity and low cost such a work could easily be turned
into an excellent teaching tool.
