if ( $child = fork ) {
     #Do Parent stuff here
} else {
     while ( $child2 = fork ) { # fork 2nd child, wait for 
          wait;                 # it to finish and re-fork
     }
     #  Do second level child stuff here
     #  Every time we finish, child # 1 starts us again
     exit;
}

##</code><code>##

if ( $child = fork ) {
     close PARENTWRITE;  # Not needed in parent
     while ( ! $child2data ) {
          $child2data = <PARENTREAD>;
     }
     #  Do Parent stuff here 
     #  after ensuring that child2 started
} else {
     close PARENTREAD;  # Not needed in child
     #  Do some processing
     while ( $child2 = fork ) { # fork 2nd child, wait for 
          wait;                 # it to finish and re-fork
     }
     #  Do second level child init stuff here

     print PARENTWRITE 1; # Let parent know we started good
     #  Do more second level child processing

     #  Every time we finish, child # 1 starts us again
     exit;
}