How to give a non-uniform effect to a simple board?

The principle is one more time very simple. Instead of one picture for tiles, we use 4 different images. There closely have the same representation, but the difference between them give this non-uniform effect:

Now in our engine, when we display a tile, we choose on of the four pictures for the sprite. To make the code easiest to use, we placed the four images in an array and we use the Math.random() method to choose a random index of the array. Here is the new engine code for constructing the game-board (from RandomBoard.java file):

...
    // Display tiles from class Tiles.
    // If the current position in the Tiles array is set to true,
    // a sprite, randomly taken from four ones, is created.
    for (int y = 0; y < Tiles.tiles.length; y++) {
      for (int x = 0; x < Tiles.tiles[y].length; x++) {
	if (Tiles.tiles[y][x]) {
	  Sprite tile = new Sprite(tileImage[((int) (Math.random()*10000)) % 4]);
	  tile.setPosition(x*tileSize, y*tileSize);
	  playfield.addSprite(tile);
	}
      }
    }
...

In the next example, we will see how to generate a complete board with animations.