Mats Lidström . Traffic. Cello & Piano. Spooky Pieces (ABRSM grade 4-8) are exciting new pieces for cello and piano from performer and composer Mats Lidström. These engaging works make a point of introducing less experienced player to techniques such as harmonics, use of mute, playing near the bridge, tremolo and glissando. The pieces contain drama, passion, wide dynamic range and swift musical contrasts.. Grade: 4 - 8