1-2 start/2006-01-20/1

state.getNextPage().getRest()

// pseudo-code
class StateWithPage implements State {
  public State getNextPage() {
     return createState(this.page + 1);
  }
  protected State createState(final int page) {
     return new StateWithPage(page);
  }
}
class StateWithPageAndColor extends StateWithPage {
  protected State createState(final int page) {
    return new StateWithPageAndColor(page, this.color);
  }
}