Solo Xtreme, Book 2: 9 X-traordinary and Challenging Piano Pieces By Melody Bober. Level: Elementary / Late Elementary. The term "xtreme" is often used in sports to indicate feats that go beyond the ordinary.The pieces in the Solo Xtreme series were written to encourage piano students to achieve similar feats. Pieces in this series move beyond single-line melodies that stay in one location, challenging students instead to move around the keyboard, cross hand-over- hand, use a variety of articula