public class TrafficLights extends World
{

    /**
     * Constructor for objects of class Traffic.
     * 
     */
    public TrafficLights()
    {    
        // Create a new world with 600x400 cells with a cell size of 1x1 pixels.
        super(800, 600, 1); 
        addObject(new Car(), 10, 25);
       addObject(new Sensor(), 300, 25);
        addObject(new Light(), 555, 165);
    }
}

public class TrafficLights extends World
{
    public TrafficLights()
    {    
        super(800, 600, 1); 
        addObject(new Car(), 10, 25);
        Light light = new Light();
        addObject(new Sensor(light), 300, 25);
        addObject(light, 555, 165);
    }
}