for my $i (2..3) {
    local $/=",";
    for my $line (0..4**$i - 1) { # you were missing -1
        print "line $line - ";
        my $num=$line;
        my @tuple;
        for my $j (0..$i-1) {
            unshift @tuple, $num%4;
            $num/=4;
        }
        print "@tuple\n";
    }
}