Structure "woodboard": (defstruct woodboard (size 'twoXfour) (length 8) (strength 'medium) ) Structure "balsa" inherits from "woodboard": (defstruct (balsa (:include woodboard (strength 'light)))) Class "board": (defclass board () ((size :accessor board-size :initarg :size :initform 'twoXfour) (length :accessor board-length :initarg :length :initform 8) (strength :accessor board-strength :initarg :strength :initform 'medium) ) ) Class "balsaboard" has "board" as a superclass: (defclass balsaboard (board) ((strength :initform 'light))) Create an instance of woodboard: > (setf b1 (make-woodboard)) Access the strength of b1: > (woodboard-strength b1) --> MEDIUM Create an instance of balsa: > (setf b2 (make-balsa)) Values of fields for b2: b2: size = twoXfour, length = 8, strength = light Create an instance of class "balsaboard": > (setf b3 (make-instance 'balsaboard)) Get the value of b3's strength: > (board-strength b3) --> LIGHT