diff --git a/src/com/codefortomorrow/advanced/chapter15/practice/animals/Animal.java b/src/com/codefortomorrow/advanced/chapter15/practice/animals/Animal.java
new file mode 100644
index 0000000..2c56942
--- /dev/null
+++ b/src/com/codefortomorrow/advanced/chapter15/practice/animals/Animal.java
@@ -0,0 +1,17 @@
+package com.codefortomorrow.advanced.chapter15.practice.animals;
+
+public abstract class Animal {
+    private String species;
+    private int age;
+    private String gender;
+    private String sound;
+
+    public Animal(String species, int age, String gender, String sound) {
+        // TODO: Complete
+    }
+
+    public void grow() {
+        // TODO: Complete
+    }
+    // TODO: Abstract Methods
+}
diff --git a/src/com/codefortomorrow/advanced/chapter15/practice/animals/Cat.java b/src/com/codefortomorrow/advanced/chapter15/practice/animals/Cat.java
new file mode 100644
index 0000000..f5148db
--- /dev/null
+++ b/src/com/codefortomorrow/advanced/chapter15/practice/animals/Cat.java
@@ -0,0 +1,20 @@
+package com.codefortomorrow.advanced.chapter15.practice.animals;
+
+public class Cat extends Animal {
+
+    // TODO: Fields
+
+    public Cat(
+        String species,
+        int age,
+        String gender,
+        String sound,
+        String color
+    ) {
+        // TODO: Complete
+    }
+
+    public void makeSound() {
+        // TODO: Complete
+    }
+}
diff --git a/src/com/codefortomorrow/advanced/chapter15/practice/animals/Dog.java b/src/com/codefortomorrow/advanced/chapter15/practice/animals/Dog.java
new file mode 100644
index 0000000..471170c
--- /dev/null
+++ b/src/com/codefortomorrow/advanced/chapter15/practice/animals/Dog.java
@@ -0,0 +1,20 @@
+package com.codefortomorrow.advanced.chapter15.practice.animals;
+
+public class Dog extends Animal {
+
+    // TODO: Fields
+
+    public Dog(
+        String species,
+        int age,
+        String gender,
+        String sound,
+        int ageDogYears
+    ) {
+        // TODO: Complete
+    }
+
+    public void makeSound() {
+        // TODO: Complete
+    }
+}
diff --git a/src/com/codefortomorrow/advanced/chapter15/practice/animals/Zebra.java b/src/com/codefortomorrow/advanced/chapter15/practice/animals/Zebra.java
new file mode 100644
index 0000000..857bf0f
--- /dev/null
+++ b/src/com/codefortomorrow/advanced/chapter15/practice/animals/Zebra.java
@@ -0,0 +1,20 @@
+package com.codefortomorrow.advanced.chapter15.practice.animals;
+
+public class Zebra extends Animal {
+
+    // TODO: Fields
+
+    public Zebra(
+        String species,
+        int age,
+        String gender,
+        String sound,
+        int numStripes
+    ) {
+        // TODO: Complete
+    }
+
+    public void makeSound() {
+        // TODO: Complete
+    }
+}
diff --git a/src/com/codefortomorrow/advanced/chapter15/solutions/animals/Animal.java b/src/com/codefortomorrow/advanced/chapter15/solutions/animals/Animal.java
new file mode 100644
index 0000000..b0ae84f
--- /dev/null
+++ b/src/com/codefortomorrow/advanced/chapter15/solutions/animals/Animal.java
@@ -0,0 +1,37 @@
+package com.codefortomorrow.advanced.chapter15.solutions.animals;
+
+public abstract class Animal {
+    private String species;
+    private int age;
+    private String gender;
+    private String sound;
+
+    public Animal(String species, int age, String gender, String sound) {
+        this.species = species;
+        this.age = age;
+        this.gender = gender;
+        this.sound = sound;
+    }
+
+    public void grow() {
+        age++;
+    }
+
+    public abstract void makeSound();
+
+    public String getSpecies() {
+        return species;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public String getGender() {
+        return gender;
+    }
+
+    public String getSound() {
+        return sound;
+    }
+}
diff --git a/src/com/codefortomorrow/advanced/chapter15/solutions/animals/Cat.java b/src/com/codefortomorrow/advanced/chapter15/solutions/animals/Cat.java
new file mode 100644
index 0000000..de1c31e
--- /dev/null
+++ b/src/com/codefortomorrow/advanced/chapter15/solutions/animals/Cat.java
@@ -0,0 +1,20 @@
+package com.codefortomorrow.advanced.chapter15.solutions.animals;
+
+public class Cat extends Animal {
+    private String color;
+
+    public Cat(
+        String species,
+        int age,
+        String gender,
+        String sound,
+        String color
+    ) {
+        super(species, age, gender, sound);
+        this.color = color;
+    }
+
+    public void makeSound() {
+        System.out.println(getSound());
+    }
+}
diff --git a/src/com/codefortomorrow/advanced/chapter15/solutions/animals/Dog.java b/src/com/codefortomorrow/advanced/chapter15/solutions/animals/Dog.java
new file mode 100644
index 0000000..9167956
--- /dev/null
+++ b/src/com/codefortomorrow/advanced/chapter15/solutions/animals/Dog.java
@@ -0,0 +1,22 @@
+package com.codefortomorrow.advanced.chapter15.solutions.animals;
+
+public class Dog extends Animal {
+    int ageInDogYears;
+
+    public Dog(
+        String species,
+        int age,
+        String gender,
+        String sound,
+        int ageInDogYears
+    ) {
+        super(species, age, gender, sound);
+        this.ageInDogYears = ageInDogYears;
+    }
+
+    public void makeSound() {
+        System.out.println(getSound());
+        System.out.println(getSound());
+        System.out.println(getSound());
+    }
+}
diff --git a/src/com/codefortomorrow/advanced/chapter15/solutions/animals/Zebra.java b/src/com/codefortomorrow/advanced/chapter15/solutions/animals/Zebra.java
new file mode 100644
index 0000000..f6a00da
--- /dev/null
+++ b/src/com/codefortomorrow/advanced/chapter15/solutions/animals/Zebra.java
@@ -0,0 +1,21 @@
+package com.codefortomorrow.advanced.chapter15.solutions.animals;
+
+public class Zebra extends Animal {
+    private int numStripes;
+
+    public Zebra(
+        String species,
+        int age,
+        String gender,
+        String sound,
+        int numStripes
+    ) {
+        super(species, age, gender, sound);
+        this.numStripes = numStripes;
+    }
+
+    public void makeSound() {
+        System.out.println(getSound());
+        System.out.println(getSound());
+    }
+}