In "Two Kinds," what is the meaning of the second piece of music at the end?

The ending of the story suggests that both of these pieces
of music are symbolically related to our lives and the process of growing up, with the
titles being very significant in terms of how we develop and teh various stages of
relationships that we have with our parents. Let us look at the last
paragraph:

readability="11">

And for the first time, or so it seemed, I
noticed the piece on the right-hand side. It was called "Perfectly Contented." I tried
to play this one as well. It had a lighter melody but the same flowing rhythm and turned
out to be quite easy. "Pleading Child" was shorter but slower; "Perfectly Contented" was
longer but faster. And after I played them both a few times, I realised they were two
halves of the same song.

Both
of these pieces of music then relate to specific stages. Note how "Pleading Child" is
actually quite short, but because it is slower, it appears to be longer. However,
"Perfectly Contented" is longer. Jing-Mei has passed through her "Pleading Child" stage,
and now, having gone through the conflict with her mother, is able to reach the stage of
being "Perfectly Contented," when she is at peace with herself and with her mother. The
story ends with the realisation that both of these stages are necessary and related to
each other.