import vtk

cone_a = vtk.vtkConeSource()

coneMapper = vtk.vtkPolyDataMapper()
coneMapper.SetInputConnection(cone_a.GetOutputPort())

coneActor = vtk.vtkActor()
coneActor.SetMapper(coneMapper)

ren1 = vtk.vtkRenderer()
ren1.AddActor(coneActor)
ren1.SetBackground(0.1, 0.2, 0.4)

renWin = vtk.vtkRenderWindow()
renWin.AddRenderer(ren1)
renWin.SetSize(300, 300)
renWin.Render()

iren = vtk.vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)

iren.Initialize()
iren.Start()