title: Random color generator
body: <p>Given this function, I want to replace the <strong>color</strong> with a random color generator.</p>
  
  <pre><code>document.overlay = GPolyline.fromEncoded({
      color: "#0000FF",
      weight: 10,
      points: encoded_points,
      zoomFactor: 32,
      levels: encoded_levels,
      numLevels: 4
  });
  </code></pre>
  
  <p>How can I do it?</p>