Study Bach’s two-part Invention in D minor, BWV 775: the right hand states the subject and the left hand imitates it two bars later. Follow each voice on its own before joining them. At the keyboard: play one voice and sing the other.
Return to Bach’s Invention in D minor, BWV 775, now for its sequences: find a short figure that is repeated step by step at a lower or higher pitch, and mark where each sequence starts and stops. At the keyboard: transpose a short sequence.