Vibrating string, sawtooth wave harmonics. Animation showing a number of oscillating strings fixed at both ends, demonstrating harmonics for sawtooth waves. A sawtooth wave is a non-sinusoidal periodic waveform resulting from the summation of sinusoidal waves (Fourier synthesis). The front string oscillates in the first harmonic, while the other strings behind represent the additive synthesis of a sawtooth wave with an increasing number of harmonics. 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, and an inertial force due to its mass.