Subject: Additional subsystem decompositions

In some recent news articles I discussed a few additional dependencies that
might naturally be added to the subsystem decomposition in the solution to
Assignment #2.  You may add these to your subsystem decomposition if you wish
to do so, and if you do, then you do not have to justify it.  Basically, I
giving you a somewhat larger space of subsystem decompositions that you can use
without having to justify them.  Feel free to use any one of them.