public void spawnFood(){
		//try 100 random tiles
		Point tile = null;
		int x = 0, y = 0;
		for(int i = 0; i < 100; i++){
			x = (int)(Math.random() * tile_width);
			y = (int)(Math.random() * tile_height);
			tile = new Point(x,y);
			if(getStateAt(tile) == TileState.OPEN){
				setStateAt(tile, TileState.FOOD);
				return;
			}
		}
		for(int ix = 0; ix < tile_width; ix++){
			for(int iy = 0; iy < tile_height; iy++){
				if(grid[ix][iy] == TileState.OPEN){
					grid[ix][iy] = TileState.FOOD;
					return;
				}
			}
		}
	}