public String toString() {
		StringBuilder b = new StringBuilder("\n---------------\n|");
		for(int i = rows - 1; i >= 0; i--) {
			for(int j = 0; j < columns; j++) {
				switch (board[i][j]) {
				case yellow: b.append("Y"); break;
				case red: b.append("R"); break;
				case empty: b.append(" "); break;
				}
				b.append("|");
			}
			b.append("\n---------------\n");
			if(i != 0) b.append("|");
		}
		
		return b.toString();
	}