Watch what Mingus does at 35 second mark. On recording...Bass players of the NY Philharmonic said he overdubbed and it couldn't be done.
I heard this story from Jamil Nasser (RIP) of the Ahmad Jamal trio. Mingus had them come to his studio and he played it for them. He then firmly dressed them down and made it clear to them that what they do can be learned easier than what he does. Doesn't look hrad but is innovative and to the ear sounds impossible.