Thoughts may be transformed when one gazes through a window at the blue sky beyond the balustrades. This notion underlies the trio and is illustrated clearly at the opening, when the viola, playing low, sustained notes strives upwards to a brief loud tutti (the barrier) from which the flute emerges, high in it's range. The process is repeated several times; other transformations include a lazy melody, a pulsating dance, and angry counterpoint to the loud rhythmic accompaniment of the harp. Beyond the fifth and final barrier lies a meditatative coda in which the harp offers a conciliatory, chorale-like passage to unite the other two instruements.
