Drawing a castle and towers with acm.graphics
here are my comments:

1) instead of having a create method for objects, why not have classes that you can instantiate? seems more clear to me

public class Tower extends GRect {
  final double width = 150;
  final double height = 600;
  public Tower() {
    super(width, height);
  }
}


2) instead of creating a GRect and then moving it, you can specify the location when you add it: add(new Tower(), 700, 250); this shows more clearly the intention of placing the tower at a certain location