// This constructor will create new state taking values from old state
public YellowState(TrafficLightState state)
: this(state.TrafficLightProperty)
{
}
// This constructor will create new state taking values from old state
public RedState(TrafficLightState state)
: this(state.TrafficLightProperty)
{
}
public TrafficLight()
{
currentState = new GreenState(this);
}