<table>
  <tr>
    <td></td>
    <td rowspan=3></td>
    <td rowspan=2></td>
  </tr>
  <tr>                    incoming_rowspan: [0, 2, 1]
     <td></td>
  </tr>
  <tr>                    incoming_rospwan: [0, 1, 0]
     <td></td>
     <td></td>
  </tr>
  <tr>                    incoming_rowspan: [0, 0, 0]
    ...
  </tr>
</table>