void Start()
{
StartCoroutine(waiter());
}
IEnumerator waiter()
{
//Rotate 90 deg
transform.Rotate(new Vector3(90, 0, 0), Space.World);
//Wait for 4 seconds
yield return new WaitForSeconds(4);
//Rotate 40 deg
transform.Rotate(new Vector3(40, 0, 0), Space.World);
//Wait for 2 seconds
yield return new WaitForSeconds(2);
//Rotate 20 deg
transform.Rotate(new Vector3(20, 0, 0), Space.World);
}