An ornament is something that's almost invariant under some transforms. For example, these ACF images are almost invariant under some rotations. Sound waves are

An ornament is something that's almost invariant under some transforms. For example, these ACF images are almost invariant under some rotations. Sound waves are almost invariant under temporal shifts. I'd argue that what makes an ornament look good is the ease of recognizing those transforms and what makes sound sound sound is the ease of recognizing those temporal shifts.