1,a,I
2,a,I
3,a,I
4,a,I
5,a,I
1,a,II
2,a,II
3,a,II
4,a,II
5,a,II
1,a,III
2,a,III
3,a,III
4,a,III
5,a,III
1,b,I
2,b,I
3,b,I
4,b,I
5,b,I
1,b,II
2,b,II
3,b,II
4,b,II
5,b,II
1,b,III
2,b,III
3,b,III
4,b,III
5,b,III

and so on.

##</code><code>##


my $i = $j = $k = 0;
for my $i (@array1) {

  for my $j  (@array2) {
  
    for my $k (@array3) {
	
	print  "$array1[k],$array2[j],$array3[i],\n";
	$k++;
}
         $j++;
}
         $k++;
}