How to Play
- Each player bets $80 a round, hoping to win a gold coin worth $100.
- Players work collaboratively, in pairs, aginst the house. Either both players win their coin, or they both lose their stake.
- They can play as many rounds as they like.
- Players are in different rooms. They can prepare any strategies or equipment before the game, but they can't communicate during each round.
- In each room the coin is flipped on to a table. The players can see whether it lands heads or tails.
- Each player has a short time to decide if they want to 'protect' the coin, by placing their hand over it.
Working out the Winner
- If neither player protects the coin, or they both do, they win.
- If one protects and the other doesn't, they lose.
- But if both coins land heads, the last two rules are reversed. Exactly one of the two heads needs to be protected to win.
Time Limit
The amount of time that a player has to decide and protect the coin depends on the distance between the rooms. Strictly, it is seven-eights of the time it would take for light to travel between the rooms. This ensures no communication is possible.
If one player is on the moon and the other is on the earth, they have about a second to decide.
Using Computers
Players are allowed to use any technology they like. They can even have a computer play for them in each room. Computers can be connected even with dedicated cables, perhaps running via a laboratory handily situated half way between the two locations.
To make this as simple as possible, the house can supply the "coinflips" via a data feed, connected to some randomness generator. They will also accept a data signal for the decision to protect the coin.
Since computers can react more quickly, the two rooms can be closer together. A distance of 2.4km between the rooms would give them 7 microseconds to decide about protecting their coins.