An E-E flat ostinato is embedded in the following accompaniment. The chords implied by the interaction of melody and accompaniment are ambiguous and analysis is difficult. One could argue that the passage is bitonal, complicated by alternating chord colors. [The chords could be a C7(flat 5, flat9, sharp 9) or a Cmi7 (flat 5, flat 9) -- or both.]

Example 13: Ambiguous Harmonies