(class-of 'fred) ⇒  #<BUILT-IN-CLASS SYMBOL 610327300>
 (class-of 2/3) ⇒  #<BUILT-IN-CLASS RATIO 610326642>

 (defclass book () ()) ⇒  #<STANDARD-CLASS BOOK 33424745>
 (class-of (make-instance 'book)) ⇒  #<STANDARD-CLASS BOOK 33424745>

 (defclass novel (book) ()) ⇒  #<STANDARD-CLASS NOVEL 33424764>
 (class-of (make-instance 'novel)) ⇒  #<STANDARD-CLASS NOVEL 33424764>

 (defstruct kons kar kdr) ⇒  KONS
 (class-of (make-kons :kar 3 :kdr 4)) ⇒  #<STRUCTURE-CLASS KONS 250020317>