In Chapter 4, we explore small/large themes!
First, we will start with a motive (also called a motif, cell, or figure): a series of tones that are distinctive, but incomplete - usually 1-2 measures long. A small theme is usually comprised of 3-4 motives. Russo suggests arranging our motives in a question/answer format, e.g. abac, where a and b pose a question and a and c answer the question. An example of a large theme might be two of our small themes back to back, e.g. abac/abac.
For this exercise, we're going to write an AABA large theme where the three A sections are made up of abac. The B section will be eefg. The B section should contrast with A sections and will contain the highest tone to help give the melody a pleasing arc.