public void tick() {
		tick++;
		if (targ == 0 && getGold() >= 600) {
			placeTower(new RockTower(this, getTowers().size()));
			targ = (int) (4 * Math.random());
		} else if (targ == 1 && getGold() >= 800) {
			placeTower(new ArrowTower(this, getTowers().size()));
			targ = (int) (4 * Math.random());
		} else if (targ == 2 && getGold() >= 1000) {
			placeTower(new SpikyTower(this, getTowers().size()));
			targ = (int) (4 * Math.random());
		} else if (targ == 3 && getGold() >= 1200) {
			placeTower(new LightningWizard(this, getTowers().size()));
			targ = (int) (4 * Math.random());
		}

		super.tick();
	}