>>35
I thought you were advocating for fewer animal examples.
>>36
If a little more complexity is what it takes to show a good use of OOP instead of a real world structure that you would never, under any circumstances, want to encode, I think that's fine. If we really want to use animals, for example, we could use an example somewhat like this:
(defclass aminal ()
(number-of-legs
brain
has-claws
...))
(defclass brain ()
(vision-center
hearing-center
...))
(defclass human-brain (brain)
(language-center
...))
It's not necessarily perfect, but (in addition to showing composition as a bonus) it does illustrate a somewhat viable use of inheritance, since brains differ in ways potentially relevant to the operation of the program, and share a certain number of slots (justifying the superclass).