diff --git a/6/w5/ShapeDemo.java b/6/w5/ShapeDemo.java
new file mode 100644
index 0000000..998237d
--- /dev/null
+++ b/6/w5/ShapeDemo.java
@@ -0,0 +1,51 @@
+public class ShapeDemo {
+    public static void main(String[] args) {
+        // 创建不同形状的对象
+        Shape circle = new Circle();
+        Shape rectangle = new Rectangle();
+        
+        // 测试drawShape方法
+        drawShape(circle);
+        drawShape(rectangle);
+    }
+    
+    /**
+     * 调用形状的draw方法
+     * @param s 形状对象
+     */
+    public static void drawShape(Shape s) {
+        s.draw();
+    }
+}
+
+/**
+ * 形状基类
+ */
+class Shape {
+    /**
+     * 绘制方法
+     */
+    public void draw() {
+        System.out.println("绘制形状");
+    }
+}
+
+/**
+ * 圆形类
+ */
+class Circle extends Shape {
+    @Override
+    public void draw() {
+        System.out.println("绘制圆形");
+    }
+}
+
+/**
+ * 矩形类
+ */
+class Rectangle extends Shape {
+    @Override
+    public void draw() {
+        System.out.println("绘制矩形");
+    }
+}
\ No newline at end of file
diff --git a/动物叫声系统.java b/动物叫声系统.java
new file mode 100644
index 0000000..563e4ee
--- /dev/null
+++ b/动物叫声系统.java
@@ -0,0 +1,31 @@
+abstract class Animal {
+    // 抽象方法：动物叫声
+    public abstract void makeSound();
+}
+
+// 2. Swimmable 接口
+interface Swimmable {
+    // 游泳方法
+    void swim();
+}
+
+// 3. Dog 类：继承 Animal，实现 Swimmable
+class Dog extends Animal implements Swimmable {
+    @Override
+    public void makeSound() {
+        System.out.println("小狗汪汪叫：汪汪汪！");
+    }
+
+    @Override
+    public void swim() {
+        System.out.println("小狗在水里狗刨式游泳！");
+    }
+}
+
+// 4. Cat 类：继承 Animal，不实现 Swimmable
+class Cat extends Animal {
+    @Override
+    public void makeSound() {
+        System.out.println("小猫喵喵叫：喵喵喵！");
+    }
+}
\ No newline at end of file
diff --git a/测试.java b/测试.java
new file mode 100644
index 0000000..6abb25b
--- /dev/null
+++ b/测试.java
@@ -0,0 +1,23 @@
+public class AnimalTest {
+    public static void main(String[] args) {
+        // 多态方式创建对象
+        Animal dog = new Dog();
+        Animal cat = new Cat();
+
+        // 调用 makeSound 方法（多态体现）
+        System.out.println("=== 动物叫声测试 ===");
+        dog.makeSound();
+        cat.makeSound();
+
+        // 测试 Swimable 接口（Dog 能游泳，Cat 不能）
+        System.out.println("\n=== 游泳能力测试 ===");
+        if (dog instanceof Swimmable) {
+            ((Swimmable) dog).swim();
+        }
+        if (cat instanceof Swimmable) {
+            ((Swimmable) cat).swim();
+        } else {
+            System.out.println("小猫不会游泳哦！");
+        }
+    }
+}
\ No newline at end of file