Imitative, polyphonic polythematic fantasia of 103 compases. In three sections with considerable relationship between them.
I: (1-31) Theme 1 imit S / T / A – B – free – S (part) – free – B – K. not paired theme
II: (31-62) Themes 2+3+4 Theme 2 based on 1, used in voice pair with 3. 4 is a variant of the head of 3. S/A (2+3) – T/B (2+3) – S/A (2+3mod) >> 4 suelto imitations >> K.
III (62 – 103) – Themes 5 a+b, 6. 5 a+b are variants of each other.
T 5a / A 5b / S5b / T5a / A5a mod / B 5a >> 6 B/A >> free >> 6 >> free K.

Structure seems to be 3 sections of 31 compases each + 10 compases of coda. Sections I & II are clearly both 31 compases + last complete statement of 6 occurs (concludes) at 93. Free material at end of section III is based on fragments of theme.
This is a fine work, closely worked out, manageable and attractive.