title: What does the argument mean in fig.add_subplot(111)?
body: <p>Sometimes I come across code such as this:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  x = [1, 2, 3, 4, 5]
  y = [1, 4, 9, 16, 25]
  fig = plt.figure()
  fig.add_subplot(111)
  plt.scatter(x, y)
  plt.show()
  </code></pre>
  
  <p>Which produces:</p>
  
  <p><img src="https://i.stack.imgur.com/yCOG3.png" alt="Example plot produced by the included code"></p>
  
  <p>I've been reading the documentation like crazy but I can't find an explanation for the <code>111</code>. sometimes I see a <code>212</code>.</p>
  
  <p>What does the argument of <code>fig.add_subplot()</code> mean?</p>