title:Notes on videos
keywords:math,statistics

# Video review
## Numberphile - The Best (and Worst) Ways to Shuffle Cards

Video: https://www.youtube.com/watch?v=AxJubaijQbI&list=PLt5AfwLFPxWLDNtOEfUgBFX5YNEhltGzt

The amount of times to shuffle depends on shuffling type:  
riffle shuffle - 7 times   
overhand shuffle - 10000  
Smooshing aka wash , corgi, chemmy - 30 sec on a edge, 1 min is enough  

If perfectly shuffled then 4.53 to guess of them papers:
https://arxiv.org/pdf/math/0501401.pdf  
https://www.jstor.org/stable/2323590?seq=1  

Trailing the Dovetail to its Lair (7 shuffles)): http://bit.ly/1xU6uPI   
Shuffling Cards and Stopping Times: http://bit.ly/1FR0ca1  
Overhand Shuffles: http://bit.ly/1LNBSuU  


### Numberphile - Shuffling Extra Footage (1/3) - Persi Diaconis
Video: https://www.youtube.com/watch?v=1jfm42Qd7Qw&list=PLt5AfwLFPxWLDNtOEfUgBFX5YNEhltGzt&index=2

Cut off phenomena happens when you shuffle and do randomness test, test
going to pass after x steps, and after x steps is always pass, like a step or a border
randomisation / shuffling schemes that doesn't have a cutoff phenomena.

Asking question is there reasonable scheme to shuffle larger decks of cards, like
in dungeon and dragons

### Numberphile - Shuffling Extra Footage (2/3) - Persi Diaconis
Video: https://www.youtube.com/watch?v=c_Hunaf0tWw&list=PLt5AfwLFPxWLDNtOEfUgBFX5YNEhltGzt&index=3

with microphone in casino where able to recreate shuffle from a sound. because casino shufflers are
perfect shufflers compare to not professional shufflers.
shuffling machines aren't good they are worse shuffling then physical shuffling.  

https://prglobalstore.com/products/automatic-card-shuffler?variant=30369630322740 maybe to get
one of those?    

Machines are going to be replaced with one that have different shuffling scheme with random number generator. Those machines you numbers that are have initial seed, and each number they add new one, there is cheats who  watch rolled out numbers on casino machine, and figure our right moment to
join the game.

### Numberphile - Shuffling Extra Footage (3/3) - Persi Diaconis
Video: https://www.youtube.com/watch?v=RIGJH12vVCY&list=PLt5AfwLFPxWLDNtOEfUgBFX5YNEhltGzt&index=4

Some history on why casinos don't use experts and don't research on math. And how businesses
assume they are right without any proper research. About how in bridge game discovered proper
probabilities of shuffling.