subplot-mosaic-4.py

import matplotlib.pyplot as plt

fig = plt.figure()

ax_1 = fig.add_subplot(2, 3, (1,2))
ax_2 = fig.add_subplot(2, 3, (3, 6))
ax_3 = fig.add_subplot(2, 3, 4)
ax_4 = fig.add_subplot(2, 3, 5)

ax_1.set_title("one")
ax_2.set_title("two")
ax_3.set_title("three")
ax_4.set_title("four")

plt.show()