12 Intermediate Cello Duets. This is another volume of lively and entertaining duets, originally composed for cello. They are designed to encourage the development of good technique. In idioms ranging from the energetic folk music of Eastern Europe to ballads and rhapsodies, More Polytekniks presents a variety of more advanced technical challenges, from vibrato, spiccato, extended position work and tenor clef to double-stopping and metrical changes. More Polytekniks may be enjoyed by a teacher and pupil duo, or by two friends of varying ability.