#!/usr/local/bin/python3

import numpy as np
import matplotlib.pyplot as plt

plt.axis([-75, 75, 50, -50])

plt.axis('on')
plt.grid(True)

plt.arrow(0, 0, 20, 0, head_length=4, head_width=3, color='k')
plt.arrow(0, 0, 0, 20, head_length=4, head_width=3, color='k')

plt.text(22, -3, 'x')
plt.text(-5, 25, 'y')

# Red box
plt.plot([-20, 20], [-20, -20], linewidth=2, color='r')
plt.plot([20, 20], [-20, 20], linewidth=2, color='r')
plt.plot([20, -20], [20, 20], linewidth=2, color='r')
plt.plot([-20, -20], [-20, 20], linewidth=2, color='r')

# Green list box
x = [-30, 30, 30, -30, -30]
y = [-30, -30, 30, 30, -30]
plt.plot(x, y, linewidth=2, color='g')

plt.show()
