vtkSmartPointer<vtkActor> squaresActor = vtkSmartPointer<vtkActor>::New();
vtkSmartPointer<vtkImageClip> clipper = vtkSmartPointer<vtkImageClip>::New();
vtkSmartPointer<vtkMarchingSquares> squares = vtkSmartPointer<vtkMarchingSquares>::New();
vtkSmartPointer<vtkPolyDataMapper> squaresMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
vtkSmartPointer<vtkActor> squaresActor = vtkSmartPointer<vtkActor>::New();
vtkSmartPointer<vtkImageClip> clipper = vtkSmartPointer<vtkImageClip>::New();
vtkSmartPointer<vtkMarchingSquares> squares = vtkSmartPointer<vtkMarchingSquares>::New();
vtkSmartPointer<vtkPolyDataMapper> squaresMapper = vtkSmartPointer<vtkPolyDataMapper>::New();