title: what is this loop doing?
body: <pre class="lang-java prettyprint-override"><code>void draw() {
    background(13);
  
    for (Line ml : middleLines) {//what kind of loop this is?
     ml.drawLine();
     ml.update();
  }
  </code></pre>
  
  <p>what is this for loop doing can't undertstand.Can any-one help me?</p>