In the following examples, repeated melodic fragments (motives) factor importantly in how new keys are introduced into an established tonal environment. Further, one of the tonal environments (either the established or the newly introduced) can be purposefully ambiguous, suggesting perhaps two or more tonal possibilities.
In what is one of Lennie Tristano’s most widely acclaimed improvised melodies, the chord progression to All of Me is visited with a torrent of running eight-note lines at a fast-paced tempo. By the beginning of the third chorus, the listener has had ample opportunity to have become acclimated to the chordal framework of the composition, complete with solo material that has been largely diatonic to the key of B-flat major. It is at this moment, however, that Tristano chooses to briefly introduce a repeating motive, beginning in the key of B major and again in the parent key of the composition.
While the tempo and usage of continuous eighth notes (common throughout the entire solo) provides the melody with a definite sense of momentum, it is the repetition of a six-beat motive, once in the foreign key and again in the original key that provides the listener with a fragment to identify with. Additionally, the fact that this motive crosses the bar line adds to the sense of momentum.
Leading up to the excerpt above from Kneebody’s Clime Pt. 2, the melody establishes itself as being firmly within an E minor or G mixolydian tonality. This is reinforced by the eight-measure ostinato in the bass, repeated throughout the five-minute composition. Once established, however, the melody briefly visits the keys of C major, A-flat lydian, and D-flat major, using the repeated ascending scale, descending arpeggio motive throughout. Once these new keys are introduced, the door is opened for additional tonal environments to be brought in. And while the E and F-sharp major melodic segments do not follow a specific motive, they do maintain the eighth-note triplet momentum of the previous melodies.