Len Mullenger wrote:

>Some compositions are palindromic I believe. Didn't Simpson write a
>palindromic quartet?

There are other pieces, Hindemith's opera Hin und zuruck and
Papineau-Couture's Piece Concertant No.1 for Piano and Strings.

Along similiar lines, the Nancarrow Canon X for player piano. The top
voice speeds up while the bottom voice slows down.  They meet in the middle
of the piece and then continue in that same fashion until the end of the
piece.

Karl