//    Instruction Example :     objectid screen.get ()


        screen.resolution.set (512,384)

        text.display ("Press a key to change screen or Press ESCAPE to exit.",CENTER,30)

        my_detect_screen ()
        screen.set (BACK)
          my_detect_screen ()
          screen.set (MID)
            my_detect_screen ()
            screen.set (FRONT)
              my_detect_screen ()
            screen.end ()
            my_detect_screen ()
          screen.end ()
          my_detect_screen ()
        screen.end ()
        my_detect_screen ()

        script.stop ()

        procedure my_detect_screen ()
          @data = screen.get ()
          screen.set (FRONT)
            switch (@data)
              case (==BACK)
                text.display ("The current screen is BACK. ",CENTER,10)
              case (==MID)
                text.display ("The current screen is MID.  ",CENTER,10)
              case (==FRONT)
                text.display ("The current screen is FRONT.",CENTER,10)
            endswitch ()
          screen.end ()
          if (keyboard.wait ()==KEY_ESCAPE)
            script.stop ()
          endif()
        end procedure