private boolean noTeleporterOnWall(Grid grid) {
		List<Teleporter> teleports = getTeleportersOfGrid(grid);
		
		for (Teleporter teleport : teleports) {
			final Position tpPos = grid.getElementPosition(teleport);
			
			for (Element e : grid.getElementsOnPosition(tpPos))
				if (e instanceof Wall)
					return false;
		}
		
		return true;
	}