The whole song just repeats a 4 measure chord progression of Bbmaj7, Cmaj7, and Ebm.
|--6-----8-----7--|
|--7-----9-----8--|
|--8-----10----9--|
|--9-----11----9--|
|-----------------|
|-----------------|
Uh, was always smart-mouthed and quick-witted
(Bmaj7)
But somethin' was always missin' like six digits
Lucky seven probably poppa
Little nigga so they picked on him, hassled him
Things changed when I hassled back, so
(repeat)Bmaj7
David hit the...
The trumpet is only playing the arpeggio of each chord.
and that's it.