Have you tried making separate groups of positive and negative cones for each of the three? Sorry, for the outer two. It would be like this, going from the outside: 1 positive 2 negative copy of 2 positive 3 negative copy of 3 positive And then grouping the groups together. I cannot try, because I have a picture rendering, but I'd really like to know whether it works. It's just something that popped in my head.

-- erlik