 Physics and psychoacoustics show that properties including frequency, amplitude, and wave shape determine the audible qualities sounds (auditorily) appear to have. To simplify, take the case of pitch, since pitch often is compared to color. Not all sounds appear to have pitch. Some sounds appear to have pitch thanks to a simple, sinusoidal pattern of vibration at some frequency in an object or in the air. Some sounds appear pitched thanks to a complex pattern of vibration that can be decomposed into sinusoidal constituents at multiple frequencies, since any pattern of vibration can be analyzed as some combination of simple sinusoids. Sounds appear pitched, however, just when they have sinusoidal constituents, or partials, that all are integer multiples of a common fundamental frequency. Sounds with pitch thus correspond to regular or periodic patterns of vibration that differ in fundamental frequency and complexity. Simple sinusoids and complex waveforms match in pitch (though they typically differ in timbre) when they share fundamental frequency. This is true even when the complex tone lacks a sinusoidal constituent at the fundamental frequency, which is referred to as the phenomenon of the missing fundamental.