    implicitPolyDataDistance = vtkImplicitPolyDataDistance()
    implicitPolyDataDistance.SetInput(cone.GetOutput())

    # create a grid
    xCoords = vtkFloatArray()
    for x, i in enumerate(np.linspace(-1.0, 1.0, 15)):
--
    implicitPolyDataDistance = vtkImplicitPolyDataDistance()
    implicitPolyDataDistance.SetInput(cone.GetOutput())

    # create a grid
    dimension = 51
    xCoords = vtkFloatArray()
--
    implicitPolyDataDistance = vtkImplicitPolyDataDistance()
    implicitPolyDataDistance.SetInput(sphereSource.GetOutput())

    # Setup a grid
    points = vtkPoints()
    step = 0.1
