title: Pushing an array inside another as a value
body: <p>How do I append an array inside another array as a value and not as a reference? Below an illustrated example:</p>
  
  <pre><code>a = []
  m = []
  i = 1
  
  # first loop
  a[0] = i      
  a[1] = i + 1
  m &lt;&lt; a #=&gt; [[1,2]]
  
  i += 1
  
  # second loop
  a[0] = i
  a[1] = i + 1
  m &lt;&lt; a #=&gt; [[2,3],[2,3]]
  </code></pre>
  
  <p>I expected something like <code>[[1,2],[2,3]]</code> instead.</p>