Like many introductory physics texts, "The Mechanical Universe" cites the spectacular 1940 collapse of the Tacoma Narrows Bridge as an example of resonance, using footage of the disaster in the "Resonance" episode. However, as more-recent expositions have emphasized, the catastrophic oscillations that destroyed the bridge were not due to simple mechanical resonance, but to a more complicated interaction between the bridge and the winds passing through it—a phenomenon known as aeroelastic flutter. This phenomenon is a kind of "self-sustaining vibration" that lies beyond the regime of applicability of the linear theory of the externally-driven simple harmonic oscillator.