c:\@Work\Perl\monks>perl -wMstrict -le
"for my $one ($1) {
   $_ = 'xx333333xx';
   for $1 (666) {
     print qq{A: '$one' $-[1] $+[1]  '$2'} if /(333)\1(xx)/;
     print qq{\$1 '$1'};
     }
   }
 ;;
 print qq{B: '$1' $-[1] $+[1]  '$2'} if /(\d\d\d)\1(\D\D)/;
"
A: '333' 2 5  'xx'
$1 '666'
B: '333' 2 5  'xx'