The first and fifth movements use the same melodic material using very different speeds and rhythms. The second and fourth movements also use their own set of like material, first appearing as a horizontal two part invention like a conversation for the woodwinds, and then stacked in vertical harmonies as a piano solo. In the third movement, the keystone of the arch, the challenge was to compose a single-line work with no harmony stated, only perhaps implied. Thus the variety is gained by changin...