Pile shuffling

Today a few words about a pile shuffling. The question is whether it is really shuffling. Firstly, what is pile shuffling? Cards are simply dealt out into a number of piles, then the piles are stacked on top of each other.

Pile shuffling is not a shuffle at all. It is a deterministic method of reordering cards and counting them while pretending to shuffle. This only ensures that cards that were next to each other are now separated. Moreover, for any number of piles, the right number of repetitions will bring the deck back to its original state. This means you can predict with 100% accuracy, where cards will end up after 'shuffling' them. The pile shuffle might be useful in games that do not require complete randomization, such as Cards Against Humanity, where no player gains a competitive advantage from being able to predict or influence the order cards are drawn in, but you shuffle to provide a different game experience.

As far as you know it now and you should be aware, that some players might use this technique to have edge over you. Then, cutting opponent's deck may be not enough. To prevent your opponent from cheating this way do a riffle shuffle or a normal shuffle of his deck. 

Most of your opponents probably aren't using some complicated way to get an advantage over you by shuffling... But these cheaters are out there, and when you get paired against one, you don't want him to mess with you.