      'width: auto' causes the measurement of the orthogonal
      box's containing block to be indefinite
      */
    }

  div#ortho-block-htb
    {
      border: blue solid 35px;
      width: 50%;
      writing-mode: horizontal-tb;
    }
  ]]></style>

 </head>

 <body>

  <div id="auto-sized-vlr-containing-block">

    <p id="sentence-before">Sentence before.</p>

    <div id="ortho-block-htb">01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 