Building a small Expert system

This application simulates a small expert system that figures out which of seven animals (if any) the system user has in mind. The system will figure out the animal by asking questions then making deductions from the replies given. A typical dialogue might be: ? Has it hair? ? yes ? Does it eat meat? ? yes ? Has it a fawn color? ? yes ? Has it dark spots? ? yes ? Your animal may be a cheetah!