content: ' Note that we need to import this file in MainScene.xml using relative path.
  
  sub ShowPlayScreen()
      m.PlayScreen = CreateObject("roSGNode", "PlayScreen")
      m.PlayScreen.ObserveField("ClassicClicked","ShowClassicScreen")
      ShowScreen(m.PlayScreen) ' show PlayScreen
  end sub
  
  sub ShowClassicScreen()
      m.ClassicScreen = CreateObject("roSGNode","ClassicScreen")
      m.ClassicScreen.ObserveField("goGameScreen","ShowGameScreen")
      ShowScreen(m.ClassicScreen)
  end sub
  
  sub ShowGameScreen()
      m.GameScreen = CreateObject("roSGNode","GameScreen")
      ShowScreen(m.GameScreen)
  end sub