static void Main(string[] args)
{
TrainSignal trainSignal = new TrainSignal();
new Car(trainSignal);
new Car(trainSignal);
new Car(trainSignal);
new Car(trainSignal);
new Car(trainSignal);
trainSignal.HereComesATrain();
}
public Car(TrainSignal trainSignal)
{
trainSignal.TrainsAComing += StopTheCar;
}