Product Group: Cello ensemble. Contributor: Waterfield, P & Lubach, G. Welcome to Polytekniks - a lively and original approach to aspects of cello technique. These versatile and entertaining duets present a variety of musical and technical challenges for the young player, from string-crossings, fourth and thumb positions and easy chords coping with unusual or tricky rhythms. Polytekniks may be used either by a teacher and pupil, or by two students at different stages of development.