$_ = "aabbccdd";
/^(\w\w)\w\w(\w\w)\w\w$/;
{
    /^\w\w(\w\w)\w\w(\w\w)$/;
    {
        print "inner: $1 $2\n";
    }
    print "mid: $1 $2\n";
}
print "outer: $1 $2\n";