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- Canon - In a canon, different voices (or instruments) sing (or play) the same melody, with no changes, but at different times. The melody is usually sung at the same pitch or an Octaves and the Major-Minor Tonal System higher or lower, but there are also canons in which the second part sings or plays the melody a perfect fourth or fifth higher or lower than the first part.
- Round - In a canon, obviously every section of the canon must "fit" with the section that comes after it. (In other words, they must sound good when sung or played at the same time). A round is a special type of canon in which the last section also fits with the first section, so that the canon can be repeated over and over without stopping. Rounds are usually pretty short and always start at the same note, or the octave.
- Fugue - A fugue usually has at least three independent parts, or voices. The different voices enter at different times on the same melodic theme (called the subject), so that the beginning may sound like a canon. But then the different voices develop the theme in different directions. A second melodic theme (called the countersubject) is usually introduced, and the middle of the fugue gets quite intricate, with the subject and countersubject popping in and out of various voices, sometimes in surprising ways (upside-down, for example).
- Countermelody or descant - Sometimes a piece of music that is basically melody-with accompaniment (homophonic) will include a single part that is truly independent of the melody. For example, a choral piece might be chordal for a few verses and then, to keep the music interesting and fresh, add an independent part for a flute or for the highest sopranos on the third verse. This is a countermelody, sometimes called a descant part. Gospel and pop singers often add countermelodies, sometimes imrovised, and classical music also contains many, many examples of countermelodies.