This is a four voice fugue. Starts with the exposition during which a subject(topic) is brought forward. The subject is followed by an answer in a different voice. I view it as a discussion of some sort. A development of the subject material follows .I view it as "brainstorming" . The conclusion or Recapitulation finishes the discussion. The fugue is not a form but rather a unique piece of music , with an underlying structure that reveals treatment of subject material in a unique way.