    normCoords = vtkCoordinate()
    normCoords.SetCoordinateSystemToNormalizedViewport()

    # Set up the mapper and actor (2D) for the grid.
    mapper = vtkPolyDataMapper2D()
    mapper.SetInputData(Grid)
--
    coordinate = vtkCoordinate()
    coordinate.SetCoordinateSystemToNormalizedViewport()

    mapper = vtkPolyDataMapper2D()
    mapper.SetInputData(poly)
    mapper.SetTransformCoordinate(coordinate)
