Elegy is a brief composition without overt repetition in its large-scale formal design. The piece is unified instead by the “developing variation” of a single motive. The variations manifest themselves in two ways. First, the motive undergoes constant intervallic variation (what is heard at the outset as a perfect eleventh appears later as a major ninth, etc.). Second, concurrent with the intervallic alterations, the motive functions in different contexts within individual phrases: the motive may begin or end a phrase, or occur abruptly in the middle of a phrase. The combination of these two processes generates a sense of musical evolution and growth within defined boundaries.
Pfaff, William P., "Elegy" (2013). Music Faculty Compositions and Performances. 1.