doesn't work.

twentyfortyeight/src/twentyfortyeight/Main.java

@@ -1,12 +1,9 @@
 package twentyfortyeight;
 
 import java.awt.Color;
-import java.time.format.TextStyle;
 import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
-import java.util.Random;
 import javalib.impworld.*;
 import javalib.worldimages.*;
 import tester.Tester;
@@ -15,9 +12,9 @@ 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.board.board.put(new Coord(0, 2), new Tile(200));
-        game.board.board.put(new Coord(0, 3), new Tile(2000));
+        game.board.board.put(new Coord(3, 1), new Tile(20));
+        game.board.board.put(new Coord(3, 2), new Tile(200));
+        game.board.board.put(new Coord(2, 3), new Tile(2000));
         game.run();
     }
 }
@@ -25,7 +22,7 @@ class Examples {
 // Config constants.
 class Util {
     // Game scale.
-    static int scale = 256;
+    static int scale = 128;
 
     // Default 2048 game board width.
     static int defaultWidth = 4;
@@ -38,7 +35,7 @@ class Util {
     }
 
     // Convert a movement to a displacement vector.
-    Coord moveDisp(Move move) {
+    static Coord moveDisp(Move move) {
         if (move.equals(Move.LEFT)) return new Coord(-1, 0);
         else if (move.equals(Move.DOWN)) return new Coord(0, -1);
         else if (move.equals(Move.UP)) return new Coord(0, 1);
@@ -75,6 +72,7 @@ class Game extends World {
     }
 
     public void onKeyEvent(String key) {
+        System.out.println("got key" + key);
         if (key.equals("left") || key.equals("h")) this.board.move(Move.LEFT);
         else if (key.equals("down") || key.equals("j"))
             this.board.move(Move.DOWN);
@@ -84,7 +82,7 @@ class Game extends World {
         else return;
     }
 
-    void run() { this.bigBang(this.width, this.width); }
+    void run() { this.bigBang(this.width, this.width, 0.01); }
 }
 
 // The possible movements.
@@ -133,12 +131,60 @@ class Board {
         else return gotten;
     }
 
+    // Set the cell at the coords.
+    void set(Coord coord, Cell cell) {
+        this.board.put(coord, cell);
+    }
+
+    // Try to move the cell at the coords to the coords.
+    void tryCellMove(Coord coord, Coord dest) {
+        Cell cell = this.get(coord);
+        Cell destCell = this.get(dest);
+
+        if (cell.isMoveable() && destCell.isReplaceable()) {
+            this.set(dest, cell);
+            this.set(coord, new Space());
+        }
+    }
+
+    // Move cell as much as possible.
+    void fullCellMove(Coord coord, Move move) {
+        Cell cell = this.get(coord);
+        Coord current = coord;
+
+        if (!cell.isMoveable()) return;
+
+        while (this.get(current.add(Util.moveDisp(move))).isReplaceable()) {
+            this.tryCellMove(current, current.add(Util.moveDisp(move)));
+            current = current.add(Util.moveDisp(move));
+        }
+    }
+
     // Move in the given direction.
     void move(Move move) {
-        for (int x = 0; x < this.sz; x++) {
-            for (int y = 0; y < this.sz; y++) {
-                // Copy logic from old code here.
-                Cell cell = this.get(new Coord(x, y));
+        System.out.println("moving");
+        for (int i = 0; i < this.sz; i ++) {
+            this.moveLine(i, move);
+        }
+    }
+
+    // Move a line of tiles.
+    void moveLine(int i, Move move) {
+        if (move.equals(Move.LEFT)) {
+            for (int x = 1; x < this.sz; x++) {
+                this.fullCellMove(new Coord(x, i), move);
+            }
+        }
+
+        else if (move.equals(Move.RIGHT)) {
+            for (int x = 0; x < this.sz - 1; x++) {
+                this.tryCellMove(new Coord(x, i), new Coord(x + 1, i));
+            }
+        }
+
+        else if (move.equals(Move.DOWN)) {
+            for (int y = this.sz - 2; y > 0; y--) {
+                this.tryCellMove(new Coord(i, y), new Coord(i , y + 1));
             }
         }
     }
@@ -155,6 +201,10 @@ abstract class Cell {
             Util.scale, Util.scale, OutlineMode.SOLID, this.col()
         );
     }
+
+    // Is this moveable?
+    boolean isMoveable() { return false; }
+    boolean isReplaceable() { return true;}
 }
 
 // A moveable tile on the board.
@@ -176,6 +226,9 @@ class Tile extends Cell {
             super.draw()
         );
     }
+
+    boolean isMoveable() { return true;}
+    boolean isReplaceable() {return false;}
 }
 
 // An empty space on the board.