(define-class Point2
  (define x 0)
  (define y 0)
  (define (init x- y-)
    (print "init")
    (set! x x-)
    (set! y y-))
  (define (pascal)
    (+ x y))
  (define (norm2)
    (+ (* x x) (* y y)))
  (define (display)
    (print x "," y " (" self ")")))

(define-class (Point3 Point2)
  (define z 0)
  (inherit norm2 pascal)
  (define (display)
    (super)
    (print (pascal))
    (print " >> " z))
  (define (norm3)
    (+ (norm2) (* z z)))
  (define (init x- y- z-)
    (super x- y-)
    (set! z z-)))

(define p2 (new Point2 1 2))
(send p2 display)
(define p3 (new Point3 1 2 3))
(send p3 display)
(print (send p3 norm3))