(define-struct p1 (first-name 
                   last-name))

(define me 
  (make-p1 "Friedrich" "Dominicus"))

(p1? me)
(p1-first-name me)
(p1-last-name me)
(set-p1-first-name! me "Someone")
(p1-first-name me)

(define-struct (p2 struct:p1) 
               (address))

(define me (make-p2 "Friedrich"
                    "Dominicus" 
                    "Bruchsal"))
(p2? me)
(p1? me)
(p1-first-name me)
(p1-last-name me)
(p2-address me)
(set-p1-first-name! me "Someone")
(p1-first-name me)