Two wizards living on the opposite sides of a country have magical coins. If each of them flips a coin at the same time, they are guaranteed to get the same out

Two wizards living on the opposite sides of a country have magical coins. If each of them flips a coin at the same time, they are guaranteed to get the same outcome. The outcome of the coinflip is random, but it's the same random number for both of them. So if you flip a coin and get e.g. "head, head, tails, head, tails" (a random sequence), you can be sure that the other wizard got the same outcome. But communication doesn't mean getting the same outcome. It means sending an information from one place to another. You would like to send some kind of message, such as "how are you?" and receive a meaningful response. Instead, you just have two random number generators that magically happen to be synchronized. (Magically synchronized random number generators can still be useful. For example, you want to make a synchronized surprise attack on an enemy that lives between you and has a perfect network of spies. Any message between the two wizards would be intercepted, and the enemy would not be surprised by the attack. However, the two wizards can agree that each day they will flip the magical coin ten times, and on the day they get a "10x heads" outcome, they will attack. Even if the enemy has intercepted this agreement, he has no idea when the attack will happen, because the wizards do not need to communicate the coinflips -- they just magically happen to be the same for both of them, so both of them will get "10x heads" on the same unpredictable day.)