why.

twentyfortyeight/src/twentyfortyeight/Main.java

@@ -10,25 +10,67 @@ import javalib.impworld.*;
 import javalib.worldimages.*;
 import tester.Tester;
 
+class Examples {
+    void testRun(Tester t) {
+        Game game = new Game();
+        game.board.board.put(new Coord(0, 0), new Tile(2));
+        game.board.board.put(new Coord(0, 1), new Tile(20));
+        game.run();
+    }
+}
+
 // Config constants.
 class Util {
     // Game scale.
-    static int scale = 24;
+    static int scale = 70;
+
+    // Default 2048 game board width.
+    static int defaultWidth = 4;
+}
+
+// A game of 2048.
+class Game extends World {
+    int score;   // The current score.
+    int sz;      // The size of the grid.
+    int width;   // The width of the image in pixels.
+    Board board; // The game board.
+
+    Game(int score, int sz, int width, Board board) {
+        this.score = score;
+        this.sz = sz;
+        this.width = this.sz * Util.scale;
+        this.board = board;
+    }
+
+    // Convenince constructor with default parameters.
+    Game() {
+        this.score = 0;
+        this.sz = Util.defaultWidth;
+        this.width = this.sz * Util.scale;
+        this.board = new Board(this.sz);
+    }
+
+    public WorldScene makeScene() {
+        WorldScene scene = new WorldScene(this.width, this.width);
+        scene.placeImageXY(this.board.draw(), this.width / 2, this.width / 2);
+        return scene;
+    }
+
+    void run() { this.bigBang(this.width, this.width); }
 }
 
 // The board on which the game is played.
 class Board {
     int sz; // The side length of the board grid square.
-    Map<Coord, Tile> board;
+    Map<Coord, Cell> board;
 
     Board(int sz) {
         this.sz = sz;
-        this.board = new HashMap<Coord, Tile>();
+        this.board = new HashMap<Coord, Cell>();
     }
 
     // Draw the board.
     WorldImage draw() {
-        WorldImage img;
         ArrayList<WorldImage> rows = new ArrayList<>();
 
         // For each row.
@@ -36,7 +78,7 @@ class Board {
             ArrayList<WorldImage> row = new ArrayList<>();
             // For each element in the row.
             for (int x = 0; x < this.sz; x++)
-                row.add(this.board.get(new Coord(x, y)).draw());
+                row.add(this.get(new Coord(x, y)).draw());
 
             // Add row to the list.
             rows.add(row.stream().reduce(
@@ -47,34 +89,64 @@ class Board {
 
         // Collapse rows into single image.
         return rows.stream().reduce(
-            new EmptyImage(),
+            new EmptyImage(), (row1, row2) -> new AboveImage(row1, row2)
-            (row1, row2) -> new BesideAlignImage(AlignModeY.BOTTOM, row1, row2)
         );
     }
 
-    // A moveable tile on the board.
+    Cell get(Coord coord) {
-    class Tile {
+        Cell gotten = this.board.get(coord);
-        int n;
 
-        Tile(int n) { this.n = n; }
+        // Check if there's something there, otherwise return empty space.
-
+        if (gotten == null) return new Space();
-        // Generate the color of the tile.
+        else return gotten;
-        Color col() {
-            int r =
-                (int)Math.min(255, 20 * (int)(Math.log(this.n) / Math.log(2)));
-            return new Color(r, r / 2 + 80, r / 3 + 20);
     }
+}
 
-        // Draw the tile.
+// A cell on the board.
+abstract class Cell {
+    // Generate the color of the tile.
+    Color col() { return Color.PINK; }
+
+    // Draw the cell.
     WorldImage draw() {
         return new RectangleImage(
             Util.scale, Util.scale, OutlineMode.SOLID, this.col()
         );
     }
+}
+
+// A moveable tile on the board.
+class Tile extends Cell {
+    int n;
+
+    Tile(int n) { this.n = n; }
+
+    Color col() {
+        // int r = (int)Math.min(255, 20 * (int)(Math.log(this.n) /
+        // Math.log(2))); return new Color(r, r / 2 + 80, r / 3 + 20);
+        return Color.RED;
     }
 
-    // Board coordinates.
+    WorldImage draw() {
-    class Coord {
+        return new OverlayImage(
+            new TextImage(
+                String.valueOf(this.n),
+                (Util.scale / Math.ceil((Math.log(this.n) / Math.log(10)))) *
+                    0.7,
+                Color.BLACK
+            ),
+            super.draw()
+        );
+    }
+}
+
+// An empty space on the board.
+class Space extends Cell {
+    Color col() { return Color.BLUE; }
+}
+
+// Board coordinates.
+class Coord {
     int x, y;
 
     Coord(int x, int y) {
@@ -88,4 +160,4 @@ class Board {
     }
 
     public int hashCode() { return 31 * Integer.hashCode(this.x + this.y); }
-    }
+}