@Override
	public String toString() {
		switch (color) {
		case -1: return ".";
		case 0: return "R";
		case 1: return "O";
		case 2: return "Y";
		case 3: return "G";
		case 4: return "B";
		case 5: return "P";
		default: return "?";
		}
	}