https://www.youtube.com/watch?v=6up1gZxXjdM

See video link. Really odd modal tune that I love and would like to play. But I can't get my head around the structure.

I can play the notes easily enough but the repeats are doing my head in. Is it just an A part and a B part being repeated irregularly? My brain can't follow it. What's the logic behind when one of the pair of players plays a part on his own?