(define (is-point-inside-rect? point rect)
  (cond ((not (point? point)) #f)
	((not (rect? rect)) #f)
	(else (and (>= (point-x point) (rect-x rect))
		   (>= (point-y point) (rect-y rect))
		   (<= (point-x point) (+ (rect-x rect) (rect-width rect)))
		   (<= (point-y point) (+ (rect-y rect) (rect-height rect))))
	      )))