title: Make a wordpress post loop add a dynamic custom style class based on order
body: <p>I have a need to include an extra style on my post loop so i end up with extra styling options, like this:</p>
  
  <pre><code>&lt;article class="first-column format-standard hentry category-uncategorized"&gt;
  &lt;article class="second-column format-standard hentry category-uncategorized"&gt;
  &lt;article class="third-column format-standard hentry category-uncategorized"&gt;
  &lt;article class="first-column format-standard hentry category-uncategorized"&gt;
  &lt;article class="second-column format-standard hentry category-uncategorized"&gt;
  &lt;article class="third-column format-standard hentry category-uncategorized"&gt;
  </code></pre>
  
  <p>And then it repeats this order. It's so i can have my posts three wide and style them nicely.</p>
  
  <p>The key one i wish to add is first-column, second column, and so on.</p>
  
  <p>Any help on what to add in wordpress for this?</p>
  
  <p>This is what currently creates this loop:</p>
  
  <pre><code>&lt;article id="post-&lt;?php the_ID(); ?&gt;" &lt;?php post_class(); ?&gt;&gt;
  </code></pre>