{
    my $pos = 0;
    sub elements(\@$) {
        my($ar, $n) = @_;

        my $range = $pos + $n < @$ar ? $pos + ($n - 1) : $#{$ar};
        my @ret = @$ar[ $pos .. $range ];
        $pos += $n;

        return @ret ? @ret : ();
    }
}

my @ar = qw(
    foo bar baz
    one two three
    ichi ni san
    xxx
);

while(my(@chunk) = elements(@ar, 3)) {
    print "got: @chunk\n";
}

__output__

got: foo bar baz
got: one two three
got: ichi ni san
got: xxx yy