Gnarles Barkley: Crazy

Hip Hop/R&B songs may have a variation with their structure. Sometimes instead of a Bridge, they will just go back to the verse, likely changing it up with a beat or some kind of variation that the other verses and finish off with the chorus.

This is a great song with a powerful hook. See not all songs have to be written EXACTLY the same, however by using the formula as a guide you can have a cohesive structure with rules you can bend.