Outline:

1. Features of object-oriented design
   • encapsulation
   • polymorphism
   • inheritance
2. Recap: inheritance
   • parent and child classes (aka superclasses and subclasses)
   • Exercise 1: exploring graphics.py
3. Designing classes to schedule activities
   • recall: Activity class from Lesson 19
   • bin packing

Explore after class:

4. Another bin packing example: Exercise 2

Reading assignment (to be completed by the next class):

• Zelle sec. 12.4-12.5 (pp. 451-456)
• https://en.wikipedia.org/wiki/Bin_packing_problem