diff --git a/factory-class-example.cs b/factory-class-example.cs
new file mode 100644
index 0000000..04e0149
--- /dev/null
+++ b/factory-class-example.cs
@@ -0,0 +1,65 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace factory1
+{
+    class Program
+    {
+        abstract class Position
+        {
+            public abstract string Title { get; }
+        }
+
+        class Clerk : Position
+        {
+            public override string Title
+            {
+                get { return "Clerk"; }
+            }
+        }
+
+        class Manager : Position
+        {
+            public override string Title
+            {
+                get { return "Manager"; }
+            }
+        }
+
+        class Programmer : Position
+        {
+            public override string Title
+            {
+                get { return "Programmer"; }
+            }
+        }
+
+        static class Factory
+        {
+            public static Position Get(int id)
+            {
+                switch (id)
+                {
+                    case 0:
+                        return new Manager();
+                    case 1:
+                    case 2:
+                        return new Clerk();
+                    default:
+                        return new Programmer();
+                }
+            }
+        }
+
+        static void Main(string[] args)
+        {
+            for (int i = 0; i < 3; i++)
+            {
+                Position position = Factory.Get(i);
+                Console.WriteLine("Where id = {0}, position = {1}", i, position.Title);
+            }
+        }
+    }
+}
diff --git a/factory-class-exercise.cs b/factory-class-exercise.cs
new file mode 100644
index 0000000..049a548
--- /dev/null
+++ b/factory-class-exercise.cs
@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace factory2
+{
+    interface IButton { }
+
+    class WinButton : IButton { }
+    class OSXButton : IButton { }
+
+    interface IGUIFactory 
+    {
+        IButton CreateButton();
+    }
+
+    class WinFactory : IGUIFactory
+    {
+
+        public IButton CreateButton()
+        {
+            return new WinButton();
+        }
+    }
+
+    class OSXFactory : IGUIFactory
+    {
+
+        public IButton CreateButton()
+        {
+            return new OSXButton();
+        }
+    }
+
+    class Program
+    {
+        public static void App(IGUIFactory factory)
+        {
+            IButton btn = factory.CreateButton();
+        }
+        static void Main(string[] args)
+        {
+            App(new OSXFactory());
+        }
+    }
+}
diff --git a/uml.cs b/uml.cs
new file mode 100644
index 0000000..1a47f15
--- /dev/null
+++ b/uml.cs
@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace uml
+{
+    class Person
+    {
+        public string Name;
+        public int Age;
+    }
+
+    class Professor : Person
+    {
+        public string Degree;
+    }
+
+    class Student : Person
+    {
+        public string level;
+    }
+
+    class Classroom
+    {
+        public Professor Professor;
+
+        public List<Student> students = new List<Student>();
+    }
+
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            Professor p = new Professor() { Age = 27, Name = "Nathan Adams", Degree = "Bachelor of science" };
+            Classroom oo70245 = new Classroom() { Professor = p };
+            oo70245.students.Add(new Student() { Name = "Microsoft Bob", Age = 18, level = "Freshman" });
+            oo70245.students.Add(new Student() { Name = "Microsoft Bob2", Age = 20, level = "Sophmore" });
+        }
+    }
+}