<a href="#x-spline-curves">3. X-spline curves</a>
        </li>
        <li>
          <a href="#x-spline-tangent">4. X-spline tangent functions</a>
        </li>
        <li>
          <a href="#rendering">5. Rendering X-spline offset curves</a>
        </li>
        <li>
          <a href="#summary">6. Summary</a>
        </li>
        <li>
          <a href="#Requirements">7. Technical requirements</a>
        </li>
        <li>
          <a href="#Resources">8. Resources</a>
        </li>
        <li>
 