When what I want is 
+----+----+----+----+
|1   |2   |3   |4   |
|    |    |    |    |
|    |    |    |    |
+----+----+----+----+

##</code><code>##

 while ($boxLine =~ s/(\.+)/sprintf("%-*d", length($1), $wordNum)/e) {
   $wordNum++
 }