code: def Sphere(pos=(0, 0, 0), r=1, c="r", alpha=1, res=24):
      
      ss = vtk.vtkSphereSource()
      ss.SetRadius(r)
      ss.SetThetaResolution(2 * res)
      ss.SetPhiResolution(res)
      ss.Update()
      pd = ss.GetOutput()
      actor = Actor(pd, c, alpha)
      actor.GetProperty().SetInterpolationToPhong()
      actor.SetPosition(pos)
      settings.collectable_actors.append(actor)
      return actor
docs: Build a sphere at position `pos` of radius `r`.
      
      |Sphere|