But the beat is only one half of a rap song’s rhythm. The other is the flow. When a rapper jumps on a beat, he adds his own rhythm. Sometimes you stay in the pocket of the beat and just let the rhymes land on the square so that the beat and flow become one. But sometimes the flow chops up the beat, breaks the beat into smaller units, forces in multiple syllables and repeated sounds and internal rhymes, or hangs a drunken leg over the last bap and keeps going, sneaks out of that bitch. The flow isn’t like time, it’s like life. It’s like a heartbeat or the way you breathe, it can jump, speed up, slow down, stop, or pound right through like a machine. If the beat is time, flow is what we do with that time, how we live through it. The beat is everywhere, but every life has to find its own flow.
— Jay-Z
