private void boardFromMatrix(Board board, char[][] chars) {
        Bubble[][] bubbles = new Bubble[chars.length][chars[0].length];
        for (int y = 0; y < chars.length; y++) {
            for (int x = 0; x < chars[0].length; x++) {
                Color c = Color.darkGray;
                switch (chars[y][x]) {
                    case 'r':
                        c = Color.red;
                        break;
                    case 'g':
                        c = Color.green;
                        break;
                    case 'b':
                        c = Color.blue;
                        break;
                    case 'y':
                        c = Color.yellow;
                        break;
                    case 'n':
                        bubbles[y][x] = null;
                        continue;
                }
                bubbles[y][x] = new Bubble(c, x, y);
            }
        }
        board.setBubbles(bubbles);
    }