title: Aspect ratio in subplots with various y-axes
body: <p>I would like the following code to produce 4 subplots of the same size with a common aspect ratio between the size of x-axis and y-axis set by me. Referring to the below example, I would like all of the subplots look exactly like the first one (upper left). What is wrong right now is that the size of the y-axis is correlated with its largest value. That is the behaviour I want to avoid.</p>
  
  <pre><code>import matplotlib.pyplot as plt
  import numpy as np
  
  def main(): 
  
      fig = plt.figure(1, [5.5, 3])
      for i in range(1,5):
          fig.add_subplot(221+i-1, adjustable='box', aspect=1) 
          plt.plot(np.arange(0,(i)*4,i))
  
      plt.show()
  
  if __name__ == "__main__": 
      main()
  </code></pre>
  
  <p>Surprisingly, matplotlib produces the right thing by default (picture below):</p>
  
  <pre><code>   import  matplotlib.pyplot as plt 
     import numpy as np 
  
     def main(): 
         fig = plt.figure(1, [5.5, 3]) 
         for i in range(1,5): 
             fig.add_subplot(221+i-1) 
              plt.plot(np.arange(0,(i)*4,i)) 
         plt.show() 
  </code></pre>
  
  <p>I just want to add to this an ability to control the aspect ratio between lengths of x and y-axes.</p>
  
  <p><img src="https://i.stack.imgur.com/DPwPs.png" alt="Here is what I am looking for:"></p>