In [51]:
import matplotlib.pyplot as plt
%pylab inline
x = arange(0.3, 2.9, 0.1)
y = sin(x)
plt.figure(num=None, figsize=(4, 4))
plt.plot(x, y)
plt.plot(1, 3)
plt.plot(-1, -1)
plt.plot(4, -1)
plt.plot(1, 2, 'b.', markersize=20.0)
plt.plot(2, 2, 'b.', markersize=20.0)
plt.grid(b=True, which='both', color='0.65',linestyle='-')
plt.show()