Area de un cuadrado

import matplotlib.pyplot as plt
from random import *
import numpy as np

xv=np.array([0,0])
yv=np.array([0,3])
plt.plot(xv,yv,'-k')

xv=np.array([0,3])
yv=np.array([3,3])
plt.plot(xv,yv,'-k')

xv=np.array([3,3])
yv=np.array([3,0])
plt.plot(xv,yv,'-k')

xv=np.array([3,0])
yv=np.array([0,0])
plt.plot(xv,yv,'-k')

plt.axis('equal')

plt.show()

def lineas1():
 xv=np.array([0,0])
 yv=np.array([0,3])
 plt.plot(xv,yv,'-k')

 xv=np.array([0,3])
 yv=np.array([3,3])
 plt.plot(xv,yv,'-k')

 xv=np.array([3,3])
 yv=np.array([3,0])
 plt.plot(xv,yv,'-k')

 xv=np.array([3,0])
 yv=np.array([0,0])
 plt.plot(xv,yv,'-k')


def lineas2():
 xv=np.array([1,1])
 yv=np.array([1,2])
 plt.plot(xv,yv,'-b')

 xv=np.array([1,2])
 yv=np.array([2,2])
 plt.plot(xv,yv,'-b')

 xv=np.array([2,2])
 yv=np.array([2,1])
 plt.plot(xv,yv,'-b')

 xv=np.array([2,1])
 yv=np.array([1,1])
 plt.plot(xv,yv,'-b')

lineas1()
lineas2()
plt.axis('equal')
plt.show()

lineas1()
lineas2()
x=random()*3
y=random()*3

if x>1 and x<2 and y>1 and y<2:
 plt.plot(x,y,'or')
else:
 plt.plot(x,y,'og')

lineas1()
lineas2()

N=100

for i in range(100):
 x=random()*3
 y=random()*3
 if x>1 and x<2 and y>1 and y<2:
  plt.plot(x,y,'or')
 else:
  plt.plot(x,y,'og')

lineas1()
lineas2()

N=100
cuenta=0
for i in range(N):
 x=random()*3
 y=random()*3
 if x>1 and x<2 and y>1 and y<2:
  plt.plot(x,y,'.r')
  cuenta=cuenta+1
 else:
  plt.plot(x,y,'.g')

area=(cuenta/N)*9.0
print(area)