Describe the attention given to unity and variety in art music as opposed to design principles in folk and popular music.

What will be an ideal response?

All music contains some balance of unity and variety or it would likely be considered noise rather than music. Art music's focus on unity and variety takes on a different dimension in part because of the length of the works. Because art music pieces tend to be much longer than popular music works, the composer's musical "blueprint" is much more detailed in a piece of art music. Major sections may be completely lifted and re-stated, for example. Importantly, art music experiments with the listener's expectations regarding repetition. Art music is considered interesting when the composer deviates from an expected pattern of repetition. Folk and popular music, on the other hand, typically follow a standard form, often creating variety by alternating between verse and chorus.