[azov]

Indeed.

The example with Birds, Ducks, and Penguins is much more colorful and fun then example with GUI widgets. It sticks. Students will remember ducks & penguins, but fall asleep before you even finish describing that boring GUI system.

Plus, nothing prevents you from using the same fun example to illustrate the second point. E.g. you can show that while penguin is a bird in real world, in your application Penguin might actually inherit from Pinniped, because it behaves like one (and it's "behaves-like", not "is-a" that we care about).

[wlievens]

If a CS student falls asleep when you talk about GUI systems, they're not in the right class.

I didn't need fluffy birds and colorful metaphors to get into this passion of mine.

The audience doesn't deserve to be patronized like that.