Árbol y tabla

  $tam = 10;
 echo "<pre>";
 for ($i = 0; $i < $tam; $i++) {
 echo str_pad(str_repeat("*", $i * 2) . "*", $tam * 2 + 1, " ", STR_PAD_BOTH) . "<br/>";
 }
 $cad="*";
 for ($i = 0; $i < $tam; $i++) {
 echo str_pad($cad, $tam * 2 + 1, " ", STR_PAD_BOTH) . "<br/>";
 $cad.="**";
 }
 ?>
 </pre>
 <table border="1">
 <?php
 for ($i = 0; $i < $tam; $i++) {
 ?>
 <tr>
 <?php
 for ($j = 0; $j < $tam; $j++) {
 ?>
 <td><?=$j==$i || $j==$tam-1-$i?"1":" " ?></td>
 <?php
 }
 ?>
 </tr>
 <?php }
 ?></table>