CSC151 2009F, Class 05: Programing the GIMP Tools

Admin:
* COOKIES!
* Don't forget to fill out the RISC survey at 
  http://www.grinnell.edu/academic/psychology/faculty/dl/risc/
  It should take about fifteen minutes.
* Extra credit
  * New experiences: The Prairie Studies farm trip tomorrow.
  * Supporting classmates: attending this weekend's home football and 
    women's soccer games (unless you play on the team).
  * You record these events on a form at the end of the semester.
* To help reduce the spread of infection, I'm bringing wipes and hand 
  sanitizer to class.  I'd recommend using the hand sanitizer at the 
  beginning and end of class.
* Are there any questions on assignment 2?
  * And does anyone need a partner or partners for the assignment?
  * Bring more questions on Monday!
* First lab writeup assigned: Write up exercises 2d, 3, and 4 for Tuesday.
* I will take questions on Scheme before the quiz.

Overview:
* Questions on yesterday's class (and anything else).
* Quiz.
* A model of images, extended.
* Coding algorithms for drawing.
* Other useful techniques.

Reflection:
* (sqrt 137641) = 371
* How do you know?
  * Divide 137641 by 371 on the computer and hope that the computer 
    can divide well
  * Hand multiply
  * Formally prove the computer's algorithm correct
  * Write an algorithm to multiply by repeated addition and use it
    to multiply

Quiz!
* Sam observes that there are insufficiently many left-handed people
  in this class.

Summary of the GIMP tools opeartion:
* Hint
  * Names start with the thing you're working on
  * Built in reference menu
  * Also reference pages