Gnawa — the trance-ceremony music (lila) of Morocco's Gnawa brotherhoods: the guembri (three-string bass lute) led by the maâlem, the iron krakeb castanets, call-and-response voices and handclaps.
How it sits: the krakeb (hat, with the soft middle rattle on shaker) loop a long–short triplet figure — strong stroke on the beat, a lighter one on the third eighth leading into the next beat. Claps reinforce beats 2 and 4. The bass layer is the guembri ostinato, a short phrase on the G minor pentatonic (G Bb C D F) that returns to G every beat or two. Tempo is the quarter: 138 is a dotted-quarter of 92; in a ceremony it accelerates steadily.
Listen for the krakeb sitting somewhere between straight and triplet — players lean the short stroke, so it can feel almost duple.
Practice: loop the guembri line alone, then add the krakeb and slowly raise the tempo the way a lila does.