diff --git a/w5/Shape.java b/w5/Shape.java
new file mode 100644
index 0000000..cad5e14
--- /dev/null
+++ b/w5/Shape.java
@@ -0,0 +1,20 @@
+class Shape {
+    public void draw() {
+        System.out.println("绘制一个形状");
+    }
+}
+
+class Circle extends Shape {
+    @Override
+    public void draw() {
+        System.out.println("绘制一个圆形 ○");
+    }
+}
+
+class Rectangle extends Shape {
+    @Override
+    public void draw() {
+        System.out.println("绘制一个矩形 ▭");
+    }
+}
+
diff --git a/w5/TestShape.java b/w5/TestShape.java
new file mode 100644
index 0000000..6137625
--- /dev/null
+++ b/w5/TestShape.java
@@ -0,0 +1,18 @@
+// 测试类
+public class TestShape {
+    // 多态方法：接收父类引用，实际调用子类重写的方法
+    public static void drawShape(Shape s) {
+        s.draw();  // 这里发生多态
+    }
+
+    public static void main(String[] args) {
+        Shape s1 = new Circle();     // 向上转型
+        Shape s2 = new Rectangle();
+
+        drawShape(s1);  // 输出：绘制一个圆形 ○
+        drawShape(s2);  // 输出：绘制一个矩形 ▭
+
+        // 直接用子类对象也可以
+        drawShape(new Circle());
+    }
+}
\ No newline at end of file