Contrapunctus I, mm. 17-22 from Die Kunst der Fuge by J.S. Bach.
The 5-6 sequence (in canon) occurs in mm. 17-20, and the lines in the rhythmic reduction show how each “5” in the middle voice becomes a dissonant suspension against each “6” in the upper voice. The reduction on top renders the 5-6 motion into a single voice.
5-6 motion is one of the oldest and simplest contrapuntal devices there is. This particular expression of it, so cunningly wrought, convoluted, and beautiful, is but one vivid illustration of what separated Bach from the contrapuntists of his time, as well as those who followed.