The poem has seven stanzas, which follow the abaccb rhyme scheme. So all of the stanzas are sestets. The poem repeats a lot of words, especially "the great god Pan," so that each stanza feels connected to the others. That repetition and the rhythm make the poem seem songlike, giving it a light and fanciful feel. However, some of Pan's actions are destructive. While his actions may come from a whimsical motive, he seems oblivious to the consequences (he acts with abandon, "as a great god can"). As the stanzas progress, they also tell a story, including how Pan as a Greek god makes a musical instrument out of a reed he finds in the river. This story reflects the belief that Pan gave humans poetry and music. The combination of story development across the stanzas and the playfulness of the lines within and across stanzas both paint a picture and tell a story.
The rhyme scheme and stanza pattern of "A Musical Instrument" mimics the appearance of a pan flute.
The rhyme scheme is ABACCB, and each stanza is made up of six lines. Each stanza is very similar to the shape of a pan flute, which is a group of pipes (or reeds) of increasing length. Thus, the rhyme scheme and stanza pattern make the poem into a pan flute.
It could also be said that each stanza is very similar to the flow of a river, as there is a constant flow throughout the poem. Pan makes his instrument from the reeds by the river.
