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Another remarkable phenomenon is pitch circularity, often likened to the visual illusion of a rotating barber pole. This illusion comprises tones that appear to descend endlessly in pitch while never truly reaching a low inaudible frequency. The illusion relies on the harmonic structure of sound, where multiple frequencies blend to create a perception of continuous descent. Such optical and auditory illusions reflect our brain’s ability to fabricate sensory information based on patterns it recognizes.