title: Overriding elements of an array in "each" loop
body: <pre><code>a = [1, 2, 3]
  a.each do |x| x+=10 end
  </code></pre>
  
  <p>After this operation array a is still <code>[1, 2, 3]</code>. How to convert it into <code>[11, 12, 13]</code>?</p>