Hi,
I would go for something like this:

foreach (@seq) {
    my ($res1, $res2, $res3);
    print "in  : $_\n";
    while (/(\w)(\w)(\w)/g) {
        $res1 .= "$1$2";
        $res2 .= "$2$3";
        $res3 .= "$3$1";
    };     
    print "out1: $res1\n";
    print "out2: $res2\n";
    print "out3: $res3\n";
};
[download]

You can skip the print statements of course.
si_lence