use warnings; use strict;
sub cartesian_product {
        @_ or return [];
        my @last = @{pop()};
        map { my @x = @$_; map { [@x, $_] } @last } cartesian_product(@_);
}
my @columns = ([1, 2, 5, 7, 3], [5, 3, 1, 8], [7, 4, 9]);
my @r = cartesian_product(@columns);
for (@r) {
        print join(" ", @$_), "\n";
}
__END__