 Many of the tracks on Gravity consist of melodic lines woven into complex rhythmic structures taken from different folk music cultures . The time signatures are not the standard 3 / 4 or 4 / 4 , but more complex signatures like 15 / 8 . Frith described in an interview how he arrived in Uppsala with his carefully written music sheets , only to find that Samla Mammas Manna could not read music . But when he played the music to them , he was " stunned by their ability to hear the details , especially the rhythmic details , that I had written . " 
