private boolean noLightGrenadeOnWall(Grid grid) {
		List<LightGrenade> lightGrenades = getLightGrenadesOfGrid(grid);
		
		for (LightGrenade lg : lightGrenades) {
			final Position lgPos = grid.getElementPosition(lg);
			
			for (Element e : grid.getElementsOnPosition(lgPos))
				if (e instanceof Wall)
					return false;
		}
		
		return true;
	}