Composer Steve Reich combines recorded voices, instruments and repetitive patterns into the unique style of music called minimalism. He has used that music to explore themes like the Holocaust, cloning, and the September 11, 2001 attacks on the World Trade Center. The Kronos Quartet will premiere Reich's new piece "WTC 9/11" at Duke Performances on Saturday, but first host Frank Stasio talks with Reich about that composition and his pioneering body of musical works.