Vibrating string, square wave damping. Animation showing a number of oscillating strings fixed at both ends, demonstrating damping for square waves. A square wave is a non-sinusoidal periodic waveform resulting from the summation of sinusoidal waves (Fourier synthesis). The front string is heavily damped, the springs behind less so. The animation shows that the higher harmonics are damped faster than the first harmonic remaining after a certain time. This model is a numerical simulation that models each string as several thousand elements. Each element is driven by a restoring force proportional to its deflection from the rest position, an inertial force due to its mass, and a frictional force depending on the velocity of each element.