I was recently at a session when one of the players pulled out square with a bunch of notes written out in letter form. He said it was a matrix and we proceeded to improvise based on the matrix. Now I guess I am very interested in the compositional uses of this said matrix. From what I gatehred it was based on Schenberg's twelve tone row. I brought it home and am having a time trying to analyze it. If anyone can offer any insight into the mysteries of this amazing tool for improvisation. I would appreciate the enlightenment.