using System;

public abstract class PatternPrinter {

    private int patternLength;

    public PatternPrinter(int patternLength) {

        this.patternLength = patternLength; 

    }

    public void Print() {

        PrintRoof();

        Random rnd = new Random();

        int specialIndex = rnd.Next(1, patternLength);

        for (int i=0; i<patternLength; i++) {

            if (i % specialIndex == 0)

                PrintBalcony();

            else {

                int roll = rnd.Next(2); // either 0 or 1

                if (roll == 0) PrintNormal();

                else PrintWindow();

            }

        }

        PrintBase();

    }

​

    public void PrintRoof() {

        Console.WriteLine("    ++    ");

        Console.WriteLine("   ++++   ");

        Console.WriteLine(" +++  +++ ");

        Console.WriteLine("++++++++++");

    }

    public void PrintBase() {

        Console.WriteLine("==========");

        Console.WriteLine("++++  ++++");

        Console.WriteLine("====  ====");

    }

    public abstract void PrintNormal();

    public abstract void PrintWindow();

    public abstract void PrintBalcony();

}

​

public class TowerPattern : PatternPrinter 

{

     public TowerPattern(int i) : base(i) // base class has parameterize costructor so we need to call it using parameterize derive class constructor

    {

    }

     public override void PrintNormal() // redefine the PrintNormal() here

     {

         Console.WriteLine("+********+");

         Console.WriteLine("+********+");

         Console.WriteLine("+********+");

         Console.WriteLine("+********+");

     }

     public override void PrintWindow() // redefine the PrintWindow() here

     {

         Console.WriteLine("+********+");

         Console.WriteLine("+*  **  *+");

         Console.WriteLine("+*  **  *+");

         Console.WriteLine("+********+");

     }

     public override void PrintBalcony() // redefine the PrintBalcony() here

     {

         Console.WriteLine("+********+");

         Console.WriteLine("+********+");

         Console.WriteLine("+        +");

         Console.WriteLine("++++++++++");

         Console.WriteLine("+********+");

     }

}

public class Program

{

    public static void Main()

    {

        TowerPattern tower = new TowerPattern(10);

        tower.Print();

    }

}

​