

::<bird
  <fly>;
  <walk>;
>;

::<penguin
  <fly>
  	<!><false>;
  <swim>;
  inherit bird;
>;

::<hawk
  inherit bird;
>;




? ::bird <swim>;
? ::penguin <swim>;
? ::bird <walk>;
? ::penguin <walk>;
? ::bird <fly>;
? ::penguin <fly>;
? ::penguin <run>;
? ::hawk <fly>;
? ::hawk <walk>;
? ::hawk <swim>;


