title: Plot normal distribution in 3D
body: <p>I am trying to plot the comun distribution of two normal distributed variables. </p>
  
  <p>The code below plots one normal distributed variable. What would the code be for plotting two normal distributed variables?</p>
  
  <pre><code>import matplotlib.pyplot as plt
  import numpy as np
  import matplotlib.mlab as mlab
  import math
  
  mu = 0
  variance = 1
  sigma = math.sqrt(variance)
  x = np.linspace(-3, 3, 100)
  plt.plot(x,mlab.normpdf(x, mu, sigma))
  
  plt.show()
  </code></pre>