title: Python: mix the letter of each word and reverse
body: <p>Given the strings <code>s1</code> and <code>s2</code> that are of the same length, creating a new string consisting of the last character of <code>s1</code> followed by the last character of <code>s2</code>, followed by the second to last character of <code>s1</code>, followed by the second to last character of <code>s2</code>, and so on (In other words the new string should consist of alternating characters of the reverse of <code>s1</code> and <code>s2</code>).  </p>
  
  <p>For example, if <code>s1</code> contained <code>hello</code> and <code>s2</code> contained <code>world</code>, then the new string should contain <code>odlllreohw</code>. Assign the new string to the variable <code>s3</code>.</p>
  
  <p>I have done this far:</p>
  
  <pre><code>s3 = ""
  for i in range(len(s1)):
      s3 = s2.reverse[i] + s1.reverse[i]
  </code></pre>
  
  <p>Where should I fix it?</p>