Listen to the hidden butt song in Hieronymous Bosch's Garden of Earthly Delights

The Hieronymous Bosch triptych painting Garden of Earthly Delights depicts a bare butt with sheet music written on it. Here's what the butt song sounds like when played.  One might expect a booty song to have a more lighthearted melody, but this butt belongs to a damned soul in the hellish portion of the triptych. That explains the dark and serious tone of the butt song.