CSC151 2007S, Class 07: Drawings as Values

Admin:
* I will miss office hours today.  
  If I'm not in my office, I'll be teaching the other section of 151. 
  You can still hang out in here (or at least next door) and ask questions.
* Monday's reading probably won't be available until Saturday night.  Sorry.
* Assignment 3 is now available.  We'll look at it quickly.
* If you aren't able to finish today's lab in class, I encourage you 
  to do so on your own.  (And to do the extra problems.)
* Quiz!

Overview:
* Thinking about drawings through composition/decomposition.
* Pure approaches vs impure approaches.
* Lab.

==Quiz==

* Clearly a lot of fun.
* If you manage to find errors (e.g., incorrect syntax), you will
  probably get extra credit.

==Lab==

* The joy of pure functions