PAD is data driven, the PAD data concepts are named Level and Occurence

Below example:
- Is two levels deep
- The level 'row' has 3 occurences
- The level 'column' has 5 occurences

PHP HTML Result 
<?php

  $row [1] ['column'] [1] ['cell'] = 11;
  $row [1] ['column'] [2] ['cell'] = 12;
  $row [1] ['column'] [3] ['cell'] = 13;
  $row [1] ['column'] [4] ['cell'] = 14;
  $row [1] ['column'] [5] ['cell'] = 15;

  $row [2] ['column'] [1] ['cell'] = 21;
  $row [2] ['column'] [2] ['cell'] = 22;
  $row [2] ['column'] [3] ['cell'] = 23;
  $row [2] ['column'] [4] ['cell'] = 24;
  $row [2] ['column'] [5] ['cell'] = 25;

  $row [3] ['column'] [1] ['cell'] = 31;
  $row [3] ['column'] [2] ['cell'] = 32;
  $row [3] ['column'] [3] ['cell'] = 33;
  $row [3] ['column'] [4] ['cell'] = 34;
  $row [3] ['column'] [5] ['cell'] = 35;

?>
 
<table border='1'>
  {row}
    <tr>
      {column}
        <td>{$cell}</td>
      {/column}
    </tr>
  {/row}
</table>
11 12 13 14 15
21 22 23 24 25
31 32 33 34 35

If not specifield for a PAD tag then default it has 1 occurence.


Just for fun, below the above example implemented in a few different ways.
Hopefully all this magic will be explained in this manual.

PHP HTML Result 
<?php

  $row    = [1,2,3];
  $column = [1,2,3,4,5];

?>
 
<table border='1'>
  {row}
    <tr>
      {column}
        <td>{$row | * 10 | + $column}</td> 
      {/column}
    </tr>
  {/row}
</table>
11 12 13 14 15
21 22 23 24 25
31 32 33 34 35 
<?php

  $short = [ [ 11,12,13,14,15 ],
             [ 21,22,23,24,25 ],
             [ 31,32,33,34,35 ] ];

?>
 
<table border='1'> 
  {short}
    <tr>
      {short}
        <td>{$short}</td>
      {/short}
    </tr>
  {/short}
</table>
11 12 13 14 15
21 22 23 24 25
31 32 33 34 35 
<?php

  for ($row = 1; $row <= 3; $row++)
    for ($col = 1; $col <= 5; $col++)
      $rows [$row] ['cols'] [$col] = TRUE;

?>
 
<table border='1'>
  {rows}
    <tr>
      {cols}
        <td>{echo (&rows:key*10) + &cols:key}</td>  
      {/cols}
    </tr>
  {/rows}
</table>
11 12 13 14 15
21 22 23 24 25
31 32 33 34 35 
<table border='1'>
  {sequence '10..30', increment=10, name='row'}
    <tr>
      {sequence '1..5', name='column'}
        <td>{$row | + $column}</td>      
      {/sequence}
    </tr>
  {/sequence}
</table>
11 12 13 14 15
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<table border='1'>
  {sequence 3}
    <tr>
      {sequence 5}
        <td>{echo ($-2 * 10) + $-1}</td>      
      {/sequence}
    </tr>
  {/sequence}
</table>
11 12 13 14 15
21 22 23 24 25
31 32 33 34 35 
<table border='1'>
  {set $row = 10}
  {while $row <= 30}
    <tr>
      {set $column = 1}
      {while $column <= 5}
        <td>{echo $row + $column}</td>  
        {increment $column}
      {/while}
    </tr>
    {set $row = $row + 10}
  {/while}
</table>
11 12 13 14 15
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31 32 33 34 35 
{data 'row'   } (1,2,3)     {/data}
{data 'column'} (1,2,3,4,5) {/data}

<table border='1'>
  {row}
    <tr>
      {column}
        <td>{$row | * 10 | + $column}</td>      
      {/column}
    </tr>
  {/row}
</table>
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31 32 33 34 35 
{data 'myJson'}
[
  { "column": [ 11, 12, 13, 14, 15 ] },
  { "column": [ 21, 22, 23, 24, 25 ] },
  { "column": [ 31, 32, 33, 34, 35 ] }
]
{/data}

{pad data='myJson'}
  <table border='1'>
    @start@
      <tr>
        {column}
          <td>{$column}</td>
        {/column}
      </tr>
    @end@
  </table>
{/pad}
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{data 'myCsv'}
AA,BB,CC,DD,EE
11,12,13,14,15
21,22,23,24,25
31,32,33,34,35
{/data}

<table border='1'>
  {myCsv}
    <tr>
      {fields}
        <td>{$value}</td>
      {/fields}
    </tr>
  {/myCsv}
</table>
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{data 'myYaml', 'level_demo.yaml'}

<table border='1'>
  {myYaml}
    <tr>
      {column}
        <td>{$column}</td>
      {/column}
    </tr>
  {/myYaml}
</table>
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{data 'myXml', 'level_demo.xml'}

<table border='1'>
  {myXml}
    <tr>
      {column}
        <td>{$column}</td>
      {/column}
    </tr>
  {/myXml}
</table>
11 12 13 14 15
21 22 23 24 25
31 32 33 34 35