<sequential>
  <html slug="html_90">
    <!-- UTF-8 characters are acceptable… HTML entities are not -->
    <h1>Inline content…</h1>
  </html>
  <video youtube="1.50:vl9xrfxcr38,1.25:qxNX4REGqx4,1.0:BGU1poJDgOY,0.75:8rK9vnpystQ" slug="S1V14_Summary" name="S1V14: Summary"/>
  <customtag tag="S1" slug="discuss_91" impl="discuss"/>
  <customtag page="70" slug="book_92" impl="book"/>
  <customtag lecnum="1" slug="slides_93" impl="slides"/>
  <poll_question name="T1_changemind_poll_foo" display_name="Change your answer" reset="false">
        <p>Have you changed your mind?</p>
        <answer id="yes">Yes</answer>
        <answer id="no">No</answer>
  </poll_question>
</sequential>
