Meanings of complex fugue in inglês

A very elaborate fantasy introduces the equally complex fugue, which bring to mind those of JS Bach.

And a complex fugue later in the movement gives a nod to the modal folk idiom of Vaughan Williams.

There is sweeping joy, and there are also halting, sarcastic marches; complex fugues, great church-shattering chants and moments where the words become sublime exhalations.