'''This example is only interesting when ran in interactive mode'''

import matplotlib.pyplot as plt
import numpy as np

# Plot circle or radius 3

an = np.linspace(0, 2*np.pi, 100)

plt.subplot(221)
plt.plot(3*np.cos(an), 3*np.sin(an))
plt.title('not equal, looks like ellipse', fontsize=10)

plt.subplot(222)
plt.plot(3*np.cos(an), 3*np.sin(an))
plt.axis('equal')
plt.title('equal, looks like circle', fontsize=10)

plt.subplot(223)
plt.plot(3*np.cos(an), 3*np.sin(an))
plt.axis('equal')
plt.axis([-3, 3, -3, 3])
plt.title('looks like circle, even after changing limits', fontsize=10)

plt.subplot(224)
plt.plot(3*np.cos(an), 3*np.sin(an))
plt.axis('equal')
plt.axis([-3, 3, -3, 3])
plt.plot([0, 4], [0, 4])
plt.title('still equal after adding line', fontsize=10)

plt.show()