Differently structured songs?

Does anyone ever write like an 18 measure loop(instead of like a 8 or 16 measure) and have it repeat at later point during a song? I wrote a part of a song and it atonal so restructuring the song to where it is more balanced is kind of complex. 

Well, the least common multiple 18 and 4 share is 36, so maybe you could incorporate that somehow? You'd have to play the loop back to back, but then you could plug in a 16 + 16 + 4 loop underneath as "counterpoint."

Or I may have just made this 36 times more confusing...

I mean it sounds like a good idea, I use a repeating 4 1/2 measure loop underneath, but the lead hand for the piano kind of goes very consonant with it making it difficult to adjust. If I can come up with some good counterpoint it sounds good.