void Start()
 {
     if (transform.position.y == tunnel.GetCenter().y)
     {
         if (Random.Range(0, 100) < 50)                                                                                                                                              //<50 means being dine to be an exeption
         {
             transform.GetComponent <ExeptionObstacleController> ().enabled = true;
         }
         else
         {
             transform.GetComponent <ObstacleRotator> ().enabled = true;
         }
     }
     else
     {
         float playerScaleY = GameObject.FindWithTag("Player").transform.lossyScale.y;                               //to not have an obstacle impossibile to avoid
         if ((transform.position.y > roofY + playerScaleY / 2) && (transform.position.y < roofY + playerScaleY))
         {
             transform.position += new Vector3(0, playerScaleY + 80, 0);                  //just over the player
         }
     }
 }
 void Awake()
 {
     tunnel = GameObject.Find("Tunnel").GetComponent <ObstacleSpawner> ();
     center = tunnel.GetCenter();
     roofY  = tunnel.GetTunnelLimits() [3];
 }