 <tr>
      <th>color</th>
      <td><p>color to use to stroke lines with - a hex code (with no alpha) or any of the 147 named CSS colors, e.g 'green', 'indigo'</p></td>
    </tr>
    <tr>
      <th>alpha</th>
      <td><p>transparency value for the line between 0 (transparent) and 1 (opaque)</p></td>
    </tr>
    <tr>
      <th>width</th>
      <td><p>stroke width in units of pixels</p></td>
    </tr>
    <tr>
      <th>type</th>
      <td><p>an integer between 1 and 6 matching the <code>lty</code> proper