    # pts = array of 6 4-tuples of vtkIdType (int) representing the faces
    #     of the cube in terms of the above vertices
    pts = [(0, 3, 2, 1), (4, 5, 6, 7), (0, 1, 5, 4),
           (1, 2, 6, 5), (2, 3, 7, 6), (3, 0, 4, 7)]

    # We'll create the building blocks of polydata including data attributes.
