title: create an NSArray of substrings from a NSString
body: <p>I have a <code>NSString</code> that contains numbers and characters. I would like to know the best way to make an <code>NSArray</code> of <code>NSStrings</code> that contain 2 characters each from the main string.</p>
  
  <p>For instance if the original <code>NSString</code> looked like this</p>
  
  <pre><code>AFC23S4QL0
  </code></pre>
  
  <p>your NSArray of substrings would look like this</p>
  
  <pre><code>ARRAY {
    AF,
    C2,
    3S,
    4Q,
    L0 
  }
  </code></pre>