The assignment was to demonstrate an understanding of 18th century counterpoint (as opposed to 16th century, which culminated in the motet). This was much more involved, as I had to consider the underlying harmonic progressions as well as the intervals between the parts. I wrote a subject, the line featured in the first four bars, that implied some typical harmony. The second part repeated the subject starting on the 5th scale degree while the first part continued with a counter-subject, quickly modulating to the key of the V chord. After the subject finished in the second part, I used a two-bar bridge to modulate back to the tonic key. The third part restated the subject with counter-subject in the second part and second counter-subject in the first, all working to imply the underlying progression. Cadence, done.
I haven't received a grade on it yet. I forgot to avoid period construction (ending the subject on the tonic and staying there). I think I did well on the rest of it.