Polyphonic texture, like so many other musical elements, cannot be categorized with any precision. One useful and important distinction, however, is between imitative polyphony and non-imitative polyphony.

Imitative polyphony results when the various lines sounding together use the same or fairly similar melodies, with one coming in shortly after another. The simplest example of imitative polyphony is a round, such as “Row, Row, Row Your Boat” or “Frère Jacques”; the richest kind is a fugue (see Chapter 10). In the following music example, you can see that each voice enters with the same notes but in staggered fashion; the second and third voices imitate the first:

Non-imitative polyphony occurs when the melodies are different from one another. An example that many will know is the typical texture of a New Orleans jazz band, with the trumpet playing the main tune, flanked top and bottom by the clarinet and the trombone playing exhilarating melodies of their own.