matplotlib figure gets deleted

In [1]: import numpy as np

In [2]: from matplotlib import pyplot as plt

In [3]: import pylab

In [4]: centerNormal = pylab.load("centerNormal")

In [5]: pointProject = pylab.load("pointProject")

In [6]: myFigure = plt.figure(figsize=(30,30))

In [7]: myAxis = myFigure.add_subplot(1,1,1)

In [8]: pointProject.shape
Out[8]: (208, 4)

In [9]: pointProject[:,0].shape
Out[9]: (208,)

In [10]: pointProject[:,2].shape
Out[10]: (208,)

In [11]: myAxis.plot(pointProject[:,0],pointProject[:,2],'ro')
Out[11]: [<matplotlib.lines.Line2D object at 0x93e7c2c>]

In [12]: myFigure.show()

In [13]: myAxis.set_aspect('equal')

In [14]: myFigure.show()
---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)

/home/tomislav/OpenFOAM/tomislav-1.5-dev-debug/run/MASTER/circleCases/hexMesh/voFoamCircleHexa/<ipython console> in <module>()

/usr/lib/python2.5/site-packages/matplotlib/backends/backend_qt4.pyc in <lambda>(*args)
    239
    240         # attach a show method to the figure for pylab ease of use
--> 241         self.canvas.figure.show = lambda *args: self.window.show()
    242
    243         def notify_axes_change( fig ):

RuntimeError: underlying C/C++ object has been deleted

In [16]: