    hex_ = vtkHexahedron()
    for i in range(0, numberOfVertices):
        hex_.GetPointIds().SetId(i, i)

    # Add the points and hexahedron to an unstructured grid
    uGrid = vtkUnstructuredGrid()
--
    hexahedron = vtkHexahedron()

    for i in range(0, len(pointCoordinates)):
        points.InsertNextPoint(pointCoordinates[i])
        hexahedron.GetPointIds().SetId(i, i)

--
    hexahedron = vtkHexahedron()
    for i in range(0, number_of_vertices):
        hexahedron.GetPointIds().SetId(i, i)

    # Add the points and hexahedron to an unstructured grid
    ug = vtkUnstructuredGrid()
--
    hexa = vtkHexahedron()
    for i, pointCoord in enumerate(pointCoords):
        points.InsertNextPoint(pointCoord)
        hexa.GetPointIds().SetId(i, i)

    # Add the hexahedron to a cell array.
