The solfege in the beginning, and the main theme, is d-t-la-sol, stated a total of three times. The phrase is played in the first measure, then repeated, and then played as the last measure. In between, the development phrases are shaped by held half steps, like t-do. The continuous eighth rhythm keeps a steady tempo and focus on the motion. Because there are little jumping intervals, combined with the rhythm, the excerpt seems lite and flowing. The main theme rhythm is characterized by a dotted eighth, sixteenth rhythm, and the descending solfege. I liked the excerpt very much, you can't go wrong with Bach.