    reverse = vtkReverseSense()

    # Choose a random subset of points.
    mask_pts = vtkMaskPoints()
    mask_pts.SetOnRatio(5)
    mask_pts.RandomModeOn()
--
    reverse = vtkReverseSense()

    # Choose a random subset of points.
    mask_pts = vtkMaskPoints()
    mask_pts.SetOnRatio(5)
    mask_pts.RandomModeOn()
