title: List of Objects being Changed when Original Object is Changed
body: <p>In Python, if I write:</p>
  
  <pre><code>a = [1]
  b = 3 * [a]
  a.append(2)
  print a, b
  </code></pre>
  
  <p>Then, the output is: </p>
  
  <pre><code>[1, 2] [[1, 2], [1, 2], [1, 2]]
  </code></pre>
  
  <p>However, when I write:</p>
  
  <pre><code>a = [1]
  b = 3 * a # notice the missing brackets here 
  a.append(2)
  print a, b
  </code></pre>
  
  <p>This turns out to be:</p>
  
  <pre><code>[1, 2] [1, 1, 1]
  </code></pre>
  
  <p>What is going on here?</p>