How rotate non consecutive elements in a list
<p>I have a List containing elements that are accessed according to their indexes. In this list I need to be able to "rotate" groups of 4 elements according to their index. For example in the list</p>

<pre><code>[a, b, c, d, e ,f , g, h, i, j, k, l]
</code></pre>

<p>I want to rotate c, f, i, l in order to get</p>

<pre><code>[a, b, l, d, e ,c , g, h, f, j, k, i]
</code></pre>

<p>How will you implement this ?</p>
