    brown = vtkBrownianPoints()
    brown.SetMinimumSpeed(0.5)
    brown.SetMaximumSpeed(1.0)
    brown.SetInputConnection(grad.GetOutputPort())
    elev = vtkElevationFilter()
    elev.SetLowPoint(-3, -3, -3)
--
    brown = vtkBrownianPoints()
    brown.SetMinimumSpeed(0.5)
    brown.SetMaximumSpeed(1.0)
    brown.SetInputConnection(grad.GetOutputPort())
    elev = vtkElevationFilter()
    elev.SetLowPoint(-3, -3, -3)
