title: LESS Mixin for loop
body: <p>I was wondering what is the most efficient way to write this:</p>
  
  <pre><code>&amp;:nth-child(1){   .animation-delay(100ms); }
  &amp;:nth-child(2){   .animation-delay(120ms);  }
  &amp;:nth-child(3){   .animation-delay(140ms);  }
  </code></pre>
  
  <p>.. into some LESS mixin that will set the animation-delay function value to +20 every iteration, while the next nth-child (+1) will be targeted, with a max iteration.</p>
  
  <p>Thanks so much!</p>