[plt-scheme] Window resize in world programs

All,

A question from my class: is there any way to resize the window in a  
world program?  Example situation:

;; world = Nat

;; world -> scene
(define (show w)
   (nw:rectangle w w 'solid 'red))

(big-bang 50 (on-tick add1 .6) (on-draw show))

Best,
Jordan