This document discusses different object-oriented programming principles for implementing a change request to allow ducks to fly. It first covers using inheritance to add a fly behavior to ducks. It then discusses using interfaces to define a fly behavior that can be implemented by different objects. A key principle is to separate the aspects that vary from what stays the same and to code to interfaces rather than implementations.

2. Duckville
More of, a friendly talk about inheritance and
composition :)

3. Disclaimer

4. Initial State

5. Change request - Fly

6. Using inheritance

7. Using inheritance

8. Using interfaces

9. Principle 1
Identify the aspects of the application that vary, and
separate them from what stays the same.

10. Using Behaviors

11. Principle 2
Design to an interface, not an implementation

12. Using Behaviors

13. Using Behaviors