[
  header ["h1" ]
  block [
    header ["h2" ]
    block [
      header ["h3" ]
      block [
        header ["h4" ]
        block [
          header ["h5" ]
          block [
            header ["h6" ]
            block [
              para ["text text" ]
            ]
            line ["text5" ]
          ]
          line ["text4" ]
        ]
        line ["text3" ]
      ]
      line ["text2" ]
    ]
    line ["text1" ]
  ]
  para ["text0 text0" ]
  figure [
    title ["untitled" ]
    verbatim [{pre
  pre
    pre
      pre
    pre
  pre
pre

pre
} ]
  ]
  line ["text0" ]
]