private void OnTriggerEnter(Collider other)
    {
        if (other.CompareTag("Cube"))
        {
            Debug.Log("cube entered");
            this.cubes.Add(other.gameObject);

            if (transform.parent.gameObject.tag == "Player")
            {
                CubeScript cs = other.gameObject.GetComponent <CubeScript>();
                cs.flashRoutine = cs.FlashCubeTimer();
                cs.canFlash     = true;
                StartCoroutine(cs.flashRoutine);
            }
        }
    }