When you write a song that already exists.
Posted: Sun Jun 06, 2021 7:14 pm
This made me laugh so much.....
Yep, he knows exactly what he's doing. 
I've done similar things while fooling around with audio software (like Audacity). I have no piano to fool around with, so I used the only instrument I have -- my voice -- to both create a bass line and a baritenor melody line. (Not at the same time, obviously).
The result wasn't too bad, even if I do say so myself.