private IEnumerator CompareCards(GameCard a, GameCard b)
    {
        yield return(new WaitForSeconds(1.0f));

        if (a.Type == b.Type)
        {
            Destroy(a.gameObject);
            Destroy(b.gameObject);
        }
        else
        {
            a.RevertToOriginalState();
            b.RevertToOriginalState();
        }
    }