CSC151 2009F, Class 23: Iterating Over Positions

Admin:
* Please keep your lab partners from yesterday.
* Are there questions on Assignment 5?
* The department is sponsoring another lunchtime talk on Friday on 
  Video Analytics.  
  + Is anyone interested in attending?  
* So that you have as much time as possible for lab, 
  I'm going to try to talk as little as possible.  
  + I will, however, answer questions on the reading.
* Sorry about the reading confusion.  Remember: Links to the reading
  should always be on the schedule.
* Next reading: Building Structures with Heterogeneous Lists
* Looking ahead: GIMP (the other one) presents Rent (Nov. 13-15)

Overview:
* Iterating over positions.
* Blends and other positionally-computed images.
* Drawing simple shapes.

Questions on HW5
* Sam, your instructions are unclear (kind of ironic, isn't it).  What
  do you want us to do?