An auditory Illusion: the Shepard-Risset Glissando

We are all familiar with the barber pole optical illusion where one sees the stripes go eternally up or climb down and never rotate:
<a href="https://en.wikipedia.org/wiki/Barberpole_illusion" target="_blank" rel="nofollow noopener noreferrer">Barberpole Illusion</a>

There is a similar auditory illusion called the Shepard - Risset Glissando.
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You can hear (and see) the effect here:


This is even more interesting: