diff --git a/src/main/java/com/example/tankbattle/Bullet.java b/src/main/java/com/example/tankbattle/Bullet.java
index 7cdd5d3..d7abac6 100644
--- a/src/main/java/com/example/tankbattle/Bullet.java
+++ b/src/main/java/com/example/tankbattle/Bullet.java
@@ -13,22 +13,20 @@ public class Bullet extends GameObject{
     private Dir dir;
 
     private boolean living = true;
-    GameModel gm = null;
     private Group group = Group.BAD;
 
-    public Bullet(int x, int y, Dir dir, Group group, GameModel gm) {
+    public Bullet(int x, int y, Dir dir, Group group) {
         this.x = x;
         this.y = y;
         this.dir = dir;
         this.group = group;
-        this.gm = gm;
 
         rect.x = this.x;
         rect.y = this.y;
         rect.width = WIDTH;
         rect.height = HEIGHT;
 
-        gm.add(this);
+        GameModel.getInstance().add(this);
     }
 
     public Group getGroup() {
@@ -50,7 +48,7 @@ public class Bullet extends GameObject{
     @Override
     public void paint(Graphics g) {
         if (!living) {
-            gm.remove(this);
+            GameModel.getInstance().remove(this);
         }
         switch (dir) {
             case LEFT:
@@ -72,6 +70,16 @@ public class Bullet extends GameObject{
         move();
     }
 
+    @Override
+    public int getWidth() {
+        return 0;
+    }
+
+    @Override
+    public int getHeight() {
+        return 0;
+    }
+
     private void move() {
         switch (dir) {
             case LEFT:
@@ -104,7 +112,7 @@ public class Bullet extends GameObject{
             this.die();
             int eX = tank.getX() + Tank.WIDTH / 2 - Explode.WIDTH / 2;
             int eY = tank.getY() + Tank.HEIGHT / 2 - Explode.HEIGHT / 2;
-            gm.add(new Explode(eX, eY, gm));
+            GameModel.getInstance().add(new Explode(eX, eY));
             return true;
         }
         return false;
diff --git a/src/main/java/com/example/tankbattle/Explode.java b/src/main/java/com/example/tankbattle/Explode.java
index 096d5ca..645219c 100644
--- a/src/main/java/com/example/tankbattle/Explode.java
+++ b/src/main/java/com/example/tankbattle/Explode.java
@@ -6,14 +6,11 @@ public class Explode extends GameObject {
     public static int WIDTH = ResourceMgr.explodes[0].getWidth();
     public static int HEIGHT = ResourceMgr.explodes[0].getHeight();
 
-    GameModel gm = null;
-
     private int step = 0;
 
-    public Explode(int x, int y, GameModel gm) {
+    public Explode(int x, int y) {
         this.x = x;
         this.y = y;
-        this.gm = gm;
 
         new Thread(() -> new Audio("audio/explode.wav").play()).start();
     }
@@ -24,7 +21,17 @@ public class Explode extends GameObject {
         g.drawImage(ResourceMgr.explodes[step++], x, y, null);
 
         if (step >= ResourceMgr.explodes.length)
-            gm.remove(this);
+            GameModel.getInstance().remove(this);
+
+    }
 
+    @Override
+    public int getWidth() {
+        return 0;
+    }
+
+    @Override
+    public int getHeight() {
+        return 0;
     }
 }
diff --git a/src/main/java/com/example/tankbattle/GameModel.java b/src/main/java/com/example/tankbattle/GameModel.java
index 8d74db1..5e6305b 100644
--- a/src/main/java/com/example/tankbattle/GameModel.java
+++ b/src/main/java/com/example/tankbattle/GameModel.java
@@ -1,9 +1,6 @@
 package com.example.tankbattle;
 
-import com.example.tankbattle.cor.BulletTankCollider;
-import com.example.tankbattle.cor.Collider;
 import com.example.tankbattle.cor.ColliderChain;
-import com.example.tankbattle.cor.TankTankCollider;
 
 import java.awt.Color;
 import java.awt.Graphics;
@@ -11,35 +8,53 @@ import java.util.ArrayList;
 import java.util.List;
 
 public class GameModel {
-    Tank myTank = new Tank(200, 400, Dir.DOWN, Group.GOOD, this);
 
-    List<Bullet> bullets = new ArrayList<>();
-    List<Tank> tanks = new ArrayList<>();
-    List<Explode> explodes = new ArrayList<>();
-    ColliderChain chain = new ColliderChain();
+    Tank myTank;
 
-    List<GameObject> objects = new ArrayList<>();
+    static List<Bullet> bullets = new ArrayList<>();
+    static List<Tank> tanks = new ArrayList<>();
+    static List<Explode> explodes = new ArrayList<>();
+    static ColliderChain chain = new ColliderChain();
+
+    static List<GameObject> objects = new ArrayList<>();
+
+    private static final GameModel INSTANCE = new GameModel();
+
+    public static GameModel getInstance(){
+        return INSTANCE;
+    }
 
     public GameModel() {
+    }
+
+    private void init(){
+        myTank = new Tank(200, 400, Dir.DOWN, Group.GOOD);
+
         int initTankCount = Integer.valueOf(PropertyMgr.get("initTankCount"));
 
         // 初始化敌方坦克
         for (int i = 0; i < initTankCount; i++) {
-            add(new Tank(50 + i * 80, 200, Dir.DOWN, Group.BAD, this));
+            add(new Tank(50 + i * 80, 200, Dir.DOWN, Group.BAD));
         }
 
+        add(myTank);
+
         add(new Wall(150, 150, 200, 50));
         add(new Wall(550, 150, 200, 50));
-        add(new Wall(500, 300, 200, 50));
-        add(new Wall(300, 500, 50, 200));
+        add(new Wall(300, 500, 200, 50));
+        add(new Wall(500, 300, 50, 200));
+    }
+
+    static {
+        getInstance().init();
     }
 
     public void add(GameObject go) {
-        this.objects.add(go);
+        objects.add(go);
     }
 
     public void remove(GameObject go) {
-        this.objects.remove(go);
+        objects.remove(go);
     }
 
     public void paint(Graphics g) {
@@ -57,7 +72,7 @@ public class GameModel {
 
         // 互相碰撞逻辑
         for (int i = 0; i < objects.size(); i++) {
-            for (int j = i + 1; j < objects.size(); j++) {
+            for (int j = 0; j < objects.size(); j++) {
                 GameObject o1 = objects.get(i);
                 GameObject o2 = objects.get(j);
 //                collider.collide(o1, o2);
diff --git a/src/main/java/com/example/tankbattle/GameObject.java b/src/main/java/com/example/tankbattle/GameObject.java
index 10d51b5..c6b2aeb 100644
--- a/src/main/java/com/example/tankbattle/GameObject.java
+++ b/src/main/java/com/example/tankbattle/GameObject.java
@@ -7,4 +7,6 @@ public abstract class GameObject {
     public int y;
 
     public abstract void paint(Graphics g);
+    public abstract int getWidth();
+    public abstract int getHeight();
 }
diff --git a/src/main/java/com/example/tankbattle/Tank.java b/src/main/java/com/example/tankbattle/Tank.java
index 978e37e..991d87b 100644
--- a/src/main/java/com/example/tankbattle/Tank.java
+++ b/src/main/java/com/example/tankbattle/Tank.java
@@ -27,15 +27,13 @@ public class Tank extends GameObject{
     int oldX, oldY;
 
     FireStrategy fs;
-    public GameModel gm;
 
-    public Tank(int x, int y, Dir dir, Group group, GameModel gm) {
+    public Tank(int x, int y, Dir dir, Group group) {
         super();
         this.x = x;
         this.y = y;
         this.dir = dir;
         this.group = group;
-        this.gm = gm;
 
         rect.x = this.x;
         rect.y = this.y;
@@ -54,6 +52,7 @@ public class Tank extends GameObject{
         } else {
             fs = new DefaultFireStrategy();
         }
+        GameModel.getInstance().add(this);
     }
 
     public Rectangle getRect() {
@@ -89,8 +88,8 @@ public class Tank extends GameObject{
     }
 
     private void move() {
-        oldX=x;
-        oldY=y;
+        oldX = x;
+        oldY = y;
 
         if (!moving) return;
         switch (dir) {
@@ -136,7 +135,7 @@ public class Tank extends GameObject{
 
     @Override
     public void paint(Graphics g) {
-        if (!living) gm.remove(this);
+        if (!living) GameModel.getInstance().remove(this);
         switch (dir) {
             case LEFT:
                 g.drawImage(this.group == Group.GOOD ? ResourceMgr.goodTankL : ResourceMgr.badTankL, x, y, null);
@@ -156,6 +155,16 @@ public class Tank extends GameObject{
         move();
     }
 
+    @Override
+    public int getWidth() {
+        return 0;
+    }
+
+    @Override
+    public int getHeight() {
+        return 0;
+    }
+
     public void setDir(Dir dir) {
         this.dir = dir;
     }
diff --git a/src/main/java/com/example/tankbattle/TankFrame.java b/src/main/java/com/example/tankbattle/TankFrame.java
index 9d19f29..189f737 100644
--- a/src/main/java/com/example/tankbattle/TankFrame.java
+++ b/src/main/java/com/example/tankbattle/TankFrame.java
@@ -11,7 +11,7 @@ import java.awt.event.WindowEvent;
 
 public class TankFrame extends Frame {
 
-    GameModel gm = new GameModel();
+    GameModel gm = GameModel.getInstance();
 
     static final int GAME_WIDTH = Integer.valueOf(PropertyMgr.get("gameWidth"));
     static final int GAME_HEIGHT = Integer.valueOf(PropertyMgr.get("gameHeight"));
diff --git a/src/main/java/com/example/tankbattle/Wall.java b/src/main/java/com/example/tankbattle/Wall.java
index bd8eb01..0d9b36b 100644
--- a/src/main/java/com/example/tankbattle/Wall.java
+++ b/src/main/java/com/example/tankbattle/Wall.java
@@ -49,4 +49,14 @@ public class Wall extends GameObject{
         g.fillRect(x, y, w, h);
         g.setColor(c);
     }
+
+    @Override
+    public int getWidth() {
+        return 0;
+    }
+
+    @Override
+    public int getHeight() {
+        return 0;
+    }
 }
diff --git a/src/main/java/com/example/tankbattle/decorator/GODecorator.java b/src/main/java/com/example/tankbattle/decorator/GODecorator.java
new file mode 100644
index 0000000..1968257
--- /dev/null
+++ b/src/main/java/com/example/tankbattle/decorator/GODecorator.java
@@ -0,0 +1,31 @@
+package com.example.tankbattle.decorator;
+
+import com.example.tankbattle.GameObject;
+
+import java.awt.Graphics;
+
+public class GODecorator extends GameObject {
+    GameObject gameObject;
+
+    public GODecorator(GameObject gameObject) {
+        this.gameObject = gameObject;
+    }
+
+    @Override
+    public void paint(Graphics g) {
+        this.x = gameObject.x;
+        this.y = gameObject.y;
+        paint(g);
+        gameObject.paint(g);
+    }
+
+    @Override
+    public int getWidth() {
+        return 0;
+    }
+
+    @Override
+    public int getHeight() {
+        return 0;
+    }
+}
diff --git a/src/main/java/com/example/tankbattle/decorator/RectDecorator.java b/src/main/java/com/example/tankbattle/decorator/RectDecorator.java
new file mode 100644
index 0000000..66f8a0c
--- /dev/null
+++ b/src/main/java/com/example/tankbattle/decorator/RectDecorator.java
@@ -0,0 +1,37 @@
+package com.example.tankbattle.decorator;
+
+import com.example.tankbattle.GameObject;
+
+import java.awt.Color;
+import java.awt.Graphics;
+
+public class RectDecorator extends GameObject {
+    GameObject gameObject;
+
+    public RectDecorator(GameObject gameObject) {
+        this.gameObject = gameObject;
+    }
+
+    @Override
+    public void paint(Graphics g) {
+        this.x = gameObject.x;
+        this.y = gameObject.y;
+
+        gameObject.paint(g);
+
+        Color c = g.getColor();
+        g.setColor(Color.YELLOW);
+        g.drawRect(x, y, gameObject.getWidth(), gameObject.getHeight());
+        g.setColor(c);
+    }
+
+    @Override
+    public int getWidth() {
+        return 0;
+    }
+
+    @Override
+    public int getHeight() {
+        return 0;
+    }
+}
diff --git a/src/main/java/com/example/tankbattle/strategy/DefaultFireStrategy.java b/src/main/java/com/example/tankbattle/strategy/DefaultFireStrategy.java
index ebb8e7c..d6e6979 100644
--- a/src/main/java/com/example/tankbattle/strategy/DefaultFireStrategy.java
+++ b/src/main/java/com/example/tankbattle/strategy/DefaultFireStrategy.java
@@ -2,8 +2,11 @@ package com.example.tankbattle.strategy;
 
 import com.example.tankbattle.Audio;
 import com.example.tankbattle.Bullet;
+import com.example.tankbattle.GameModel;
+import com.example.tankbattle.GameObject;
 import com.example.tankbattle.Group;
 import com.example.tankbattle.Tank;
+import com.example.tankbattle.decorator.RectDecorator;
 
 public class DefaultFireStrategy implements FireStrategy{
 
@@ -11,7 +14,7 @@ public class DefaultFireStrategy implements FireStrategy{
     public void fire(Tank t) {
         int bX = t.x + Tank.WIDTH / 2 - Bullet.WIDTH / 2;
         int bY = t.y + Tank.HEIGHT / 2 - Bullet.HEIGHT / 2;
-        new Bullet(bX, bY, t.dir, t.group, t.gm);
+        GameModel.getInstance().add(new RectDecorator(new Bullet(bX, bY, t.dir, t.group)));
 
         if(t.group == Group.GOOD) new Thread(()->new Audio("audio/tank_fire.wav").play()).start();
     }
diff --git a/src/main/java/com/example/tankbattle/strategy/FourDirFireStrategy.java b/src/main/java/com/example/tankbattle/strategy/FourDirFireStrategy.java
index fc9f399..eb59d1a 100644
--- a/src/main/java/com/example/tankbattle/strategy/FourDirFireStrategy.java
+++ b/src/main/java/com/example/tankbattle/strategy/FourDirFireStrategy.java
@@ -14,7 +14,7 @@ public class FourDirFireStrategy implements FireStrategy{
         int bY = t.y + Tank.HEIGHT / 2 - Bullet.HEIGHT / 2;
         Dir[] dirs = Dir.values();
         for(Dir dir : dirs) {
-            new Bullet(bX, bY, dir, t.group, t.gm);
+            new Bullet(bX, bY, dir, t.group);
         }
         if(t.group == Group.GOOD) new Thread(()->new Audio("audio/tank_fire.wav").play()).start();
     }