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I think that it is thought (https://en.wikipedia.org/wiki/Riffle_shuffle_permutation https://en.wikipedia.org/wiki/Riffle_shuffle_permutation) that seven riffle
by mhb 3y ago
I think that it is thought (https://en.wikipedia.org/wiki/Riffle_shuffle_permutation https://en.wikipedia.org/wiki/Riffle_shuffle_permutation) that seven riffle shuffles randomize a deck. So you may be misremembering that eight returns it to the original state.
- dragontamer 3y agoRiffle shuffles have randomness because it's assumed no human can: 1. Pick up exactly 26 cards. 2. Shuffle exactly alternating left-right-left-right across all 26 cards. But both of these feats are possible with practice. Repeat this perfect riffle shuffle enough times and the deck returns to it's exact original state. It's just simple math at that point, but it does mean you need perfection on every action. ---------- When a normie riffle shuffles, of course it's random. The issue is that magicians are ridiculously skilled in secret ways that are incredibly difficult to detect. That is: a magician can look like they're shuffling, but in reality they're actually seeding and returning the deck to a state they want it to be in for their tricks. Or a cheater at poker for that matter. ------- That's okay though. If you can 'only' pickup exactly 26 cards consistently, you are skilled enough to perfect cut, which is still enough for a lot of tricks.
- gjhr 3y agohttps://en.wikipedia.org/wiki/Riffle_shuffle_permutation#Perfect_shuffles https://en.wikipedia.org/wiki/Riffle_shuffle_permutation#Per... Shows that perfect shuffles can return the deck to the original state.