Bach's 2 part and 3 part inventions are a case study in counterpoint,
http://www.youtube.com/watch?v=AIxHPqEqvy4Since they were written long before there was polyphony, Bach arranged for multiple clavichords playing simultaneously.
Counterpoint is two or more independent melodic lines occurring at the same time. If there is a melody accompanied by a rhythmic counterpart, this is
not counterpoint. Canons, rounds and rondos, and fugues are all examples of counterpoint.