    boolean = vtkImplicitBoolean()
    boolean.SetOperationTypeToDifference()
    # boolean.SetOperationTypeToUnion()
    # boolean.SetOperationTypeToIntersection()
    boolean.AddFunction(box)
    boolean.AddFunction(sphere)
--
    boolean = vtkImplicitBoolean()
    boolean.AddFunction(cylinder)
    boolean.AddFunction(sphere)

    clipper = vtkClipPolyData()
    clipper.SetInputConnection(plane.GetOutputPort())
--
    booleanUnion = vtkImplicitBoolean()
    booleanUnion.AddFunction(sphere)
    booleanUnion.AddFunction(sphere2)
    booleanUnion.SetOperationType(0)  # boolean Union

    extract = vtkExtractGeometry()
--
    theCone = vtkImplicitBoolean()
    theCone.SetOperationTypeToIntersection()
    theCone.AddFunction(cone)
    theCone.AddFunction(vertPlane)
    theCone.AddFunction(basePlane)

--
    theCream = vtkImplicitBoolean()
    theCream.SetOperationTypeToDifference()
    theCream.AddFunction(iceCream)
    theCream.AddFunction(bite)

    # The sample function generates a distance function from the
