import numpy as np
import matplotlib.pyplot as plt

for i in range (0,10,2):
    
    for k in range (0,5):
        x=np.array([4-i,4-i])
        y=np.array([2,2-k])
        
        x1=np.array([4,4-i])
        y1=np.array([2-k,2-k])

        
        plt.plot(x1,y1,'-ob')
        plt.plot(x,y,'-ob')
plt.grid(axis='x')
plt.grid(axis='y')
plt.show()