in my last reply, I mentioned /e, here I made a little trick to explain, the examples at least looks interesting to me ;-)

$a = "1234567890";
$a =~ s/(\d)/$1 x $1/g;
print $a, "\n";
$a =~ s/(\d)/$1 x $1/ge;
print $a, "\n";
$a =~ s/(\d{2})/$1 x $1/g;
print $a, "\n";
$a =~ s/(\d{2})/$1 x $1/ge;
print $a, "\n";
[download]

cut and paste to your kit, and try it.