Polymorphism

I think polymorphism is:

• Objects may respond differently to the same message.
• Response is a function of the "state" of the object.
• Response may also be a function of the "state" of another object.
• During instantiation, the constructor(s) can produce different flavors of the same object.
For the nerds:
• Constructors can be overloaded.

Also true, but not polymorphism is:

For the nerds:
• Inheritance extends a class resulting in new properties (see inheritance)
• Methods (other than constructors) can be overloaded (but not operators).

The Incredible Machine demonstration

• By changing the state of the a machine (e.g. the orientation of a kettle) different behavior ensues.
• By changing global variables (e.g. gravity) machines behave differently.