diff --git a/w6/Animal.class b/w6/Animal.class
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index 0000000..554a799
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diff --git a/w6/Animal.java b/w6/Animal.java
new file mode 100644
index 0000000..b07d6fa
--- /dev/null
+++ b/w6/Animal.java
@@ -0,0 +1,3 @@
+public abstract class Animal {
+    public abstract void makeSound();
+}
\ No newline at end of file
diff --git a/w6/Cat.class b/w6/Cat.class
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index 0000000..28e8428
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diff --git a/w6/Cat.java b/w6/Cat.java
new file mode 100644
index 0000000..5a0c4b4
--- /dev/null
+++ b/w6/Cat.java
@@ -0,0 +1,6 @@
+public class Cat extends Animal {
+    @Override
+    public void makeSound() {
+        System.out.println("Meow!");
+    }
+}
\ No newline at end of file
diff --git a/w6/Dog.class b/w6/Dog.class
new file mode 100644
index 0000000..8c15b1d
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diff --git a/w6/Dog.java b/w6/Dog.java
new file mode 100644
index 0000000..4880968
--- /dev/null
+++ b/w6/Dog.java
@@ -0,0 +1,11 @@
+public class Dog extends Animal implements Swimmable {
+    @Override
+    public void makeSound() {
+        System.out.println("Woof!");
+    }
+
+    @Override
+    public void swim() {
+        System.out.println("Dog is swimming");
+    }
+}
\ No newline at end of file
diff --git a/w6/Main.class b/w6/Main.class
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diff --git a/w6/Main.java b/w6/Main.java
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index 0000000..282827d
--- /dev/null
+++ b/w6/Main.java
@@ -0,0 +1,14 @@
+public class Main {
+    public static void main(String[] args) {
+        Animal[] animals = new Animal[2];
+        animals[0] = new Dog();
+        animals[1] = new Cat();
+
+        for (Animal animal : animals) {
+            animal.makeSound();
+            if (animal instanceof Swimmable) {
+                ((Swimmable) animal).swim();
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/w6/Swimmable.class b/w6/Swimmable.class
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index 0000000..23e4cc7
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diff --git a/w6/Swimmable.java b/w6/Swimmable.java
new file mode 100644
index 0000000..b7a501e
--- /dev/null
+++ b/w6/Swimmable.java
@@ -0,0 +1,3 @@
+public interface Swimmable {
+    void swim();
+}
\ No newline at end of file