On November 7, 1940, the Tacoma Narrows Bridge collapsed. An explanation based on resonance was offered at that time, but in 1990, a new model was considered . Assuming that a cable cannot be described with the usual Hooke's law, it set up a nonlinear model with vertical and torsional motion. This Demonstration uses another equation presented in 1999  that avoided linearizing the torsional equation to avoid removing a wide variety of behavior. A sinusoidal forcing term was introduced with amplitude and frequency , while corresponds to the initial angle. Cases with slight increases for small torsional forcing with a transitioning to large oscillations can be observed, which is what presumably happened at Tacoma Narrows.