Row spans
```
% pandoc -f html --columns 24 -t ansi
<table>
  <thead>
    <tr>
      <td rowspan="3">1</td>
      <td>2</td>
      <td>3</td>
      <td>4</td>
      <td rowspan="4">5</td>
      <td>6</td>
    </tr>
    <tr>
      <td>2</td>
      <td colspan="2" rowspan="2">3</td>
      <td>6</td>
    </tr>
    <tr>
      <td rowspan="2">2</td>
      <td>6</td>
    </tr>
    <tr>
      <td>1</td>
      <td>3</td>
      <td>4</td>
      <td>6</td>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td colspan="2">a</td>
      <td rowspan="2">c</td>
      <td>d</td>
      <td>e</td>
      <td>f</td>
    </tr>
    <tr>
      <td>a</td>
      <td>b</td>
      <td colspan="3" rowspan="2">d</td>
    </tr>
    <tr>
      <td>a</td>
      <td>b</td>
      <td>c</td>
    </tr>
  </tbody>
  <tfoot>
    <tr>
      <td colspan="2" rowspan="4">A</td>
      <td>C</td>
      <td>D</td>
      <td colspan="2" rowspan="3">E</td>
    </tr>
    <tr>
      <td>C</td>
      <td>D</td>
    </tr>
    <tr>
      <td>C</td>
      <td>D</td>
    </tr>
    <tr>
      <td>C</td>
      <td>D</td>
      <td>E</td>
      <td>F</td>
    </tr>
  </tfoot>
</table>
^D
1   2   3   4   5   6
    2   3           6
    2               6
1       3   4       6
─── ─── ─── ─── ─── ───
a       c   d   e   f
a   b       d
a   b   c
─── ─── ─── ─── ─── ───
A       C   D   E
        C   D
        C   D
        C   D   E   F]8;;\
```

Empty rows
```
% pandoc -f native --columns 12 -t ansi
[ Table
    ( "" , [] , [] )
    (Caption Nothing [])
    [ ( AlignDefault , ColWidthDefault )
    , ( AlignDefault , ColWidthDefault )
    , ( AlignDefault , ColWidthDefault )
    ]
    (TableHead
       ( "" , [] , [] )
       [ Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 3)
               (ColSpan 2)
               [ Plain [ Str "1" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "3" ] ]
           ]
       , Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "3" ] ]
           ]
       , Row ( "" , [] , [] ) []
       , Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "1" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "2" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "3" ] ]
           ]
       ])
    [ TableBody
        ( "" , [] , [] )
        (RowHeadColumns 0)
        []
        [ Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "1" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "2" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 2)
                (ColSpan 1)
                [ Plain [ Str "3" ] ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "1" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 4)
                (ColSpan 1)
                [ Plain [ Str "2" ] ]
            ]
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "1" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "3" ] ]
            ]
        , Row ( "" , [] , [] ) []
        , Row
            ( "" , [] , [] )
            [ Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "1" ] ]
            , Cell
                ( "" , [] , [] )
                AlignDefault
                (RowSpan 1)
                (ColSpan 1)
                [ Plain [ Str "3" ] ]
            ]
        ]
    ]
    (TableFoot
       ( "" , [] , [] )
       [ Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "1" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "2" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 2)
               (ColSpan 1)
               [ Plain [ Str "3" ] ]
           ]
       , Row ( "" , [] , [] ) []
       , Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "1" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "2" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 3)
               (ColSpan 1)
               [ Plain [ Str "3" ] ]
           ]
       , Row
           ( "" , [] , [] )
           [ Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "1" ] ]
           , Cell
               ( "" , [] , [] )
               AlignDefault
               (RowSpan 1)
               (ColSpan 1)
               [ Plain [ Str "2" ] ]
           ]
       , Row ( "" , [] , [] ) []
       ])
]
^D
1       3
        3
1   2   3
─── ─── ───
1   2   3
1   2
1       3
1       3
─── ─── ───
1   2   3
1   2   3
1   2]8;;\
```