A student writes about problem 8 on the assignment you just turned in. I 
did not understand his previous description, so he wrote this:

  Hi Dr. Patt,

  I noticed that your office hours are 
  after class today, so here's a copy of the problem 
  in question.  Sorry if this is
  wasting your time at all.  

No, it is not wasting my time.

    I DO know how to use the prescribed method in the book.  
    I'm just wondering if I'm actually
    doing something that WON'T work.  
    Will this diagram work for this particular problem?

    <<Enclosed was a diagram of a NAND gate with two inputs, 
    in0 and in1.  There was an inverter on the input to the 
    NAND gate that carried in0.>>


No, what you are doing is fine.  The TA, under my direction, does not 
want you spending a lot of time thinking about how to come up with the 
simplest logic circuit.  You will have plenty of that in 316.  For our purposes 
I want you to know one simple way to implement thee functions, so you feel 
comfortable that these things can actually be built, and there is no magic 
involved.

If you want to look for a simpler circuit, I won't tell you you can't.  But 
it will take time from a whole lot of other things that I think you need to 
spend time on this semester.

In any case, it is up to you.  What you did is certainly not wrong.

I am glad you are enjoying the course.  Hope that continues.

Yale Patt

     Thanks a lot,

     <<name withheld>>

     P.S.  I'm really enjoying your class.  It's making 
     a lot of things that I only understood peripherally 
     make a lot more sense.