public void initialization() {
		int x = (int) (Math.random() * (3  + 1));
		int y = (int) (Math.random() * (3  + 1));
		int r = (int) (Math.random() * 2);
		this.set(x, y, r==0 ? 2 : 4);
		
		r = (int) (Math.random() * 2);
		while (this.get(x, y) != 0) {
			x = (int) (Math.random() * (3  + 1));
			y = (int) (Math.random() * (3  + 1));
		}
		this.set(x, y, r==0 ? 2 : 4);
	}