public boolean add(TextGrid grid){
		if(getWidth() != grid.getWidth()
			|| getHeight() != grid.getHeight()) return false;
		int width = getWidth();
		int height = getHeight();
		for(int yi = 0; yi < height; yi++){
			for(int xi = 0; xi < width; xi++){
				if(get(xi, yi) == ' ') set(xi, yi, grid.get(xi, yi));
			}
		}
		return true;
	}