Great effect, great method. However, buyer beware.
I received 2 Double Takes from Penguin
and in both cases the decks were misassembled and I had to use other decks to correct the problem of
having duplicates in the red and blue back cards.
I emailed Penguin about this and
suggested that whoever was assembling the decks needed to be fired. It's quite easy to take a red
and blue deck and correctly assemble 2 Double Take decks without having duplicates.