title: How to reshape a Ruby array
body: <p>Having an array</p>
  
  <pre><code>a = [1, 2, 3, 4, 5, 6]
  </code></pre>
  
  <p>I want to reshape it to</p>
  
  <pre><code>a = [[1, 2], [3, 4], [5, 6]]
  </code></pre>
  
  <p>I've had an impression that there was a specific method for this. I've just been through Array class reference, but failed to find it. Does anyone remember?</p>