>>> import matplotlib.pyplot as plt
>>> fig = plt.figure()
>>> ax = fig.add_subplot(111)
>>> ax.plot((1, 3, 1))
[<matplotlib.lines.Line2D object at 0x0290B750>]
>>> plt.show()

>>>
>>> fig1 = plt.figure()
>>> bx = fig1.add_subplot(111)
>>> bx.plot((1, 3, 1))
[<matplotlib.lines.Line2D object at 0x029E8210>]
>>> plt.show()

easy_install ipython

ipython -pylab

In[1]: ...

plt.close()