       $rez !.:= (. .) ;
        $rez := #I_BUILD ( $rez #TAIL ( $dim ) #TAIL ( $sub ) ) ;
PRINT (. 'here  $rez [ -1 ]=' $rez [ -1 ] .);
        IF $rez [ -1 ] = NULL ->
          $rez := #LTAIL ( $rez )
        FI ;
