(
(Point Object
    (field x 0)
    (field y 0)
    (method setx (newx) (block (:= x newx) this))
    (method sety (newy) (block (:= y newy) this))
    (method getx () x)
    (method gety () y)
    (method size () 1)
    (method grade () (* (@ this size) (+ x y)))
)

(Colorpoint Point 
    (field c (new Color))
    (method setc (newc) (block (:= c newc) this))
    (method size () (@ c hue)))

(Color Object)

(Blue Color 
  (method hue () 1))

(Red Color
  (method hue () 2))

(Green Color
  (method hue () 3))
)

(local (cp (@ (@ (new Colorpoint) setc (new Red)) setx 10))
   (@ cp grade))  
{should evaluate to 20}