public String toString(){
		String output = "";
		for(int row=-1; row<=getHeight(); row++){
			for(int col=-1; col<=getWidth(); col++){
				output += isValid(col, row) ? grid[row][col]==null?" ":"¥" : "¥";
				output += col!=getWidth()?" ":"";
			}
			output += row!=getHeight()?"\n":"";
		}
		return output;
	}