def print_fractures():
    plt.subplot(212)
plt.plot([1, 2, 3, 4])

def histogram():
    plt.subplot(211)
plt.hist(random(1000), 100)
plt.xlabel('Spacing (m)', fontsize=15)
plt.ylabel('Frequency (count)', fontsize=15)
histogram()
print_fractures()
plt.axis('equal')
plt.show()
matplotlib: multiple plots on one figure