Canonic Variations on "Vom Himmel hoch da komm' ich her"
In the next section the right hand (marked “forte” (loud)) moves in fast notes while the pedal plays the chorale tune and the bottom part of the left hand plays it in canon upside down at the second (pedal starts on C, left hand canon imitates starting on B).  Then the right and left hands swap round and there is a canon at the ninth.