Bad OO Design in C#

BadDesign1.cs

public class BankAccount
{
  public BankAccount(string AccountNumber)
  {
    this.AccountNumber = AccountNumber;
  }

  public string AccountNumber { get; private set; }
  public double AccountBalance { get; set; }
  public double Interest { get; private set; }
  private const double InterestRate = 5.5;

  // calculating interest business logic
  public void CalculateInterest()
  {
    Interest =  (InterestRate * AccountBalance) / 100;
  }

  public void SaveMoney(double amount)
  {
    AccountBalance = AccountBalance + amount;
  }

  public void WithdrawMoney(double amount)
  {
    AccountBalance = AccountBalance - amount;
  }
}

BadDesign2.cs

public class Shape
{
  const int CIRCLE = 1;
  const int RECTANGLE = 2;
  int TYPE = 0;

  private double radius;
  private double width;
  private double length;

  public double Area()
  {
    switch (TYPE)
    {
      case CIRCLE:
        return Math.PI * radius;
      case RECTANGLE:
        return width * length;
      default:
        return 0;
    }
  }

  public void CreateCircle(double radius)
  {
      this.radius = radius;
      this.TYPE = CIRCLE;
  }

  public void CreateRectangle(double length, double width)
  {
      this.width = width;
      this.length = length;
      this.TYPE = RECTANGLE;
  }
}

BadDesign3.cs

public interface IShape 
{
  public double Area();    
}

public class Rectangle : IShape 
{
	public double width {get; set; }
	public double length {get; set; }
	
	private Rectangle(){}
	
	public Rectangle(double width, double length)
	{
		this.width = width;
		this.length = length;
	}
	
	public double Area()
	{
		return this.width * this.length;
	}
}

public class Square : Rectangle
{
  public double edge { get; set; }

  public Square(double edge) : base(edge, edge)
  {
    this.edge = edge;
  }
}

BadDesign4.cs

public interface Vehicle
{
  void Fly();
  void Drive();
}

public class Car : Vehicle
{
  public void Drive() 
  { 
    // Implement drive here
  }

  public void Fly() 
  {
    throw new Exception("Can not fly");
  }
}

public class Plane : Vehicle
{
  public void Drive() 
  {
    throw new Exception("Not really a good idea");
  }

  public void Fly()
  {
    // Implement fly here
  }
}

BadDesign5.cs

public interface IOutputter
{
  void Print(string output);
}

public class ConsoleOutputter : IOutputter
{
  public void Print(string output)
  {
    System.Console.Write(output);
  }
}

public class MockOutputter : IOutputter
{
    public void Print(string output)
    {
        // do nothing
    }
}

public class CommandInvoker
{
    public void Invoke(ConsoleOutputter outputter)
    {
        outputter.Print("Hello World");
    }
}