public IEnumerator coBuilder()
    {
        if (Physics.BoxCast(activeCell.transform.position, new Vector3(0.5f, 0.1f, 0.5f), Vector3.up, Quaternion.identity, 1.0f))
        {
            buildMenu.transform.Find("warningText").GetComponent <Text>().text = "enemies in cell.";
            yield break;
        }

        GameObject testTower = Instantiate(Globals.gm.tower, new Vector3(activeCell.transform.position.x, 0.59f, activeCell.transform.position.z), activeCell.transform.rotation);

        testTower.GetComponent <MeshRenderer>().enabled = false;
        testTower.transform.GetChild(0).GetComponent <MeshRenderer>().enabled = false;

        GameObject testEnemy = (GameObject)Object.Instantiate(simpleEnemy, Globals.em.transform.position, Globals.em.transform.rotation);

        testEnemy.GetComponent <MeshRenderer>().enabled = false;

        yield return(null);


        if (testEnemy.GetComponent <NavMeshAgent>().pathStatus != NavMeshPathStatus.PathComplete)
        {
            buildMenu.transform.Find("warningText").GetComponent <Text>().text = "blocks path";
            Destroy(testTower);
            Destroy(testEnemy);
            yield break;
        }

        foreach (NavMeshAgent jBond in Globals.em.GetComponentsInChildren <NavMeshAgent>())
        {
            if (jBond.pathStatus != NavMeshPathStatus.PathComplete)
            {
                buildMenu.transform.Find("warningText").GetComponent <Text>().text = "blocks path";
                Destroy(testTower);
                Destroy(testEnemy);
                yield break;
            }
        }

        Destroy(testTower);
        Destroy(testEnemy);

        buildMenu.transform.Find("warningText").GetComponent <Text>().text = "";
        buildMenu.active = false;
        Globals.pm.AddMoney(-towerCost);
        activeCell.BuildTower();
        activeCell = null;
    }