Len writes, in reply to John Smyth:

>This should be stated "all squares are rectangles, but not all rectangles
>are squares." And by analogy, "all music is sound, but not all sound is
>music".

You know, it makes just as much sense the other way around: "All sound is
music, but not all music is sound."  It's even a pun.

Steve Schwartz, putting the cat amongst the pigeons again