Uh... time lapse, bars rhyming, heart's bottomless pit
Overtime, Earl’s rhymes plumb the depths of his heart. He’s finding out how deep it really goes. A pit is also where some prisoners are held (this would tie in “bars”). If the bars are rotting, then his rapping (bars) is suffering.
Time lapse cause it skips from before he went to Samoa, to after.
Also, if the pendulum mentioned in the hook does refer to that Edgar Allan Poe story “The Pit and the Pendulum,” this line adds the pit. The man locked in the room with the swinging pendulum discovers a deep pit. The man wants to find out what is in the pit but can not, without falling in and dying. Earl might feel that way about his emotions.
We may even speculate, that these bars are the Earl (track) style rap, hiding a more sensitive essence, not releasing it. Pitchfork speculated that the new album will be less Earl and more Luper, less graphic boasting and more emotions. It all sticks with the following bars (“mobbing deep”).
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