C# wait X-Seconds in Code before continue in Code?

actually i’m coding a Traffic-light-System. and now i stuck at the point of changing from red to green. How can i wait in the code before it continues, but dont stop the whole Game.

actually i have this, but this stops the whole game


i need to light up the yellow light for about 2 seconds, then it should turn on the Green light, how to do this?

Quick example in C#:

public class TrafficLight : MonoBehaviour {
    	void Start () {
    		StartCoroutine (GreenYellowRed ());
    	IEnumerator GreenYellowRed()
    		while (true) {
    			Debug.Log ("Green");
    			yield return new WaitForSeconds(3.0f);
    			Debug.Log ("Yellow");
    			yield return new WaitForSeconds(1.0f);
    			Debug.Log ("Red");
    			yield return new WaitForSeconds(3.0f);

im pretty useless scripter but i needed the same thing and so i did it with calculateing stuff and it does not need some kind of really complicated stuff i think this may help you:

public int one;
public int two = 50;

if (one <= two){

one = one -1;

if (one == 40){


if (one == 30){




if (one == 0){

one = two;


So far so good. What if I need to wait for some period of time from a class that have to be instantiated and not inheriting from MonoBehaviour ? How can I do that ? Thread sleep is not acceptable, also I don’t have acces to coroutines. And by the way I also want to be able to wait in the Utility class where every method is static and have to be accessed from anywhere.