Mayeb have a look at the source code for List::Permutor ( Source ). It is pretty well commented and should help.

I would just use this module or similar to do the heavy lifting directly rather than trying to roll my own (Yes, even you can use CPAN) .

Sorry I can't be of more help, time is short for me, but i hope you get this sorted out! I think the key lies in the way List::Permutor handles a list of *any* length, as opposed to your static three-tier loop. Have a look at that and see how you get on.

Again, sorry I can't be more help.