Heads or Tails is a simple game, which consists in throwing a coin to then find what their side was facing up after his fall. It is commonly used to choose between two alternatives or to resolve a dispute between two parties. This method of choice necessarily result has only two possibilities, which have the same probability of occurrence. A frequent use is the decision of who will make the initial move in some activity. In football, for example, the coin decides who will get the right to choose the field or the ball.