import matplotlib.pyplot as plt

plt.subplot(221)
plt.xticks([])
plt.yticks([])
plt.text(0.5, 0.5, "subplot(221)", ha="center", va="center", size=24, alpha=.5)

plt.subplot(222)
plt.xticks([])
plt.yticks([])
plt.text(0.5, 0.5, "subplot(222)", ha="center", va="center", size=24, alpha=.5)

plt.subplot(223)
plt.xticks([])
plt.yticks([])
plt.text(0.5, 0.5, "subplot(223)", ha="center", va="center", size=24, alpha=.5)

plt.subplot(224)
plt.xticks([])
plt.yticks([])
plt.text(0.5, 0.5, "subplot(224)", ha="center", va="center", size=24, alpha=.5)

plt.show()