my @a = qw(a0 a1 a2);
my @b = qw(b0 b1 b2);
my @c = qw(c0 c1 c2 c3 c4);
my @d = qw(d0 d1 d2 d3 d4);

print '(',join(',', one_each(@a, @b)),")\n";
print '(',join(',', one_each(@a, @b)),")\n";
print '(',join(',', one_each(@c, @d)),")\n";
print '(',join(',', one_each(@c, @d)),")\n";

##</code><code>##

(a0,b0)
(a1,b1)
(c2,d2)
()