--
An open block can be an anonymous container,
or it can masquerade as any other block.
--
>>>
Document
  { docMeta =
      Meta
        { docTitle = []
        , docTitleAttributes = Nothing
        , docAuthors = []
        , docRevision = Nothing
        , docAttributes = fromList [ ( "sectids" , "" ) ]
        }
  , docBlocks =
      [ Block
          mempty
          Nothing
          (OpenBlock
             [ Block
                 mempty
                 Nothing
                 (Paragraph
                    [ Inline
                        mempty
                        (Str
                           "An open block can be an anonymous container,\nor it can masquerade as any other block.")
                    ])
             ])
      ]
  }