for my $p0 (1     .. 5-1) {
for my $p1 ($p0+1 .. 5-1) {
    print(
        substr('12345', 0, $p0),
        "|",
        substr('12345', $p0, $p1-$p0),
        "|",
        substr('12345', $p1, 5-$p1),
        "\n",
    );
}}