Gambler's Ruin, the card game
- Take two packs of 52 cards - pack A and pack B
- Separate out 26 cards from pack A and spread them out
- Optionally remove some of the black cards from pack B
Repeatedly
- Shuffle the pack B and deal one card
- If it's black swap out a red card from the spread cards with a black from pack A
- If it's red swap out a black card from the spread cards with a red from pack A
The game ends when the spread out cards are all the same colour.
Black cards spread out
Black cards shuffled
This game implements Gambler's ruin. The house is red and the gambler is black. If no cards are removed from pack B then the odds of red or black winning a game are even, otherwise there is house advantage. If there were an infinite number of red cards in pack A then it is guaranteed that black would eventually go bankrupt.