IEnumerator SetStage()
    {
        numGoals        = 0;
        numClearedGoals = 0;
        TerrainGroup.ClearElements();
        GoalGroup.ClearElements();
        PushableGroup.ClearElements();
        PlayerGroup.ClearElements();
        CameraController.visibles.Clear();

        yield return(new WaitForSeconds(0.1f));

        if (stage == 1)
        {
            SetStage1();
        }
        else if (stage == 2)
        {
            SetStage2();
        }
        else if (stage == 3)
        {
            SetStage3();
        }
        else if (stage == 4)
        {
            SetStage4();
        }
        else
        {
            Outro();
        }
    }