diff --git a/Lesson_4/Task_4/Interfaces/IFlyable.cs b/Lesson_4/Task_4/Interfaces/IFlyable.cs
new file mode 100644
index 0000000..c76dd45
--- /dev/null
+++ b/Lesson_4/Task_4/Interfaces/IFlyable.cs
@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace LiskovSubstitution.Interfaces
+{
+    public interface IFlyable
+    {
+        public void Fly();
+    }
+}
diff --git a/Lesson_4/Task_4/Perfomance.cs b/Lesson_4/Task_4/Perfomance.cs
new file mode 100644
index 0000000..f2ee7ed
--- /dev/null
+++ b/Lesson_4/Task_4/Perfomance.cs
@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace LiskovSubstitution
+{
+    public class Perfomance
+    {
+        public void PerformActions()
+        {
+            //Hmmmm...
+        }
+    }
+}
diff --git a/Lesson_4/Task_4/Program.cs b/Lesson_4/Task_4/Program.cs
new file mode 100644
index 0000000..25f7fca
--- /dev/null
+++ b/Lesson_4/Task_4/Program.cs
@@ -0,0 +1,16 @@
+using LiskovSubstitution.Vehicles;
+
+// A plane has an engine, and is able to fly
+Plane plane = new Plane();
+plane.Fly();
+plane.StartEngine();
+
+// A car cannot fly, CS1061 if attempted
+Car car = new Car();
+// car.Fly();
+car.StartEngine();
+
+// Same for motorcycle
+Motorcycle motorcycle = new Motorcycle();
+// motorcycle.Fly();
+motorcycle.StartEngine();
diff --git a/Lesson_4/Task_4/Task_4.csproj b/Lesson_4/Task_4/Task_4.csproj
new file mode 100644
index 0000000..f02677b
--- /dev/null
+++ b/Lesson_4/Task_4/Task_4.csproj
@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net7.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>
diff --git a/Lesson_4/Task_4/Vehicles/Car.cs b/Lesson_4/Task_4/Vehicles/Car.cs
new file mode 100644
index 0000000..b8a52dc
--- /dev/null
+++ b/Lesson_4/Task_4/Vehicles/Car.cs
@@ -0,0 +1,12 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace LiskovSubstitution.Vehicles
+{
+    public class Car : Vehicle
+    {
+    }
+}
diff --git a/Lesson_4/Task_4/Vehicles/Motorcycle.cs b/Lesson_4/Task_4/Vehicles/Motorcycle.cs
new file mode 100644
index 0000000..96b6f43
--- /dev/null
+++ b/Lesson_4/Task_4/Vehicles/Motorcycle.cs
@@ -0,0 +1,12 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace LiskovSubstitution.Vehicles
+{
+    public class Motorcycle : Vehicle
+    {
+    }
+}
diff --git a/Lesson_4/Task_4/Vehicles/Plane.cs b/Lesson_4/Task_4/Vehicles/Plane.cs
new file mode 100644
index 0000000..3e0f0c2
--- /dev/null
+++ b/Lesson_4/Task_4/Vehicles/Plane.cs
@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+using LiskovSubstitution.Interfaces;
+
+namespace LiskovSubstitution.Vehicles
+{
+    public class Plane : Vehicle, IFlyable
+    {
+        public virtual void Fly()
+        {
+            Console.WriteLine("It's flying?");
+        }
+    }
+}
diff --git a/Lesson_4/Task_4/Vehicles/Vehicle.cs b/Lesson_4/Task_4/Vehicles/Vehicle.cs
new file mode 100644
index 0000000..d9a2a88
--- /dev/null
+++ b/Lesson_4/Task_4/Vehicles/Vehicle.cs
@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace LiskovSubstitution.Vehicles
+{
+    public class Vehicle
+    {
+        public virtual void StartEngine()
+        {
+            Console.WriteLine("The engine is starting");
+        }
+    }
+}