No lo puedo resolver. Quiero saber que esta mal

Question

using System;
using System.Collections.Generic;

namespace Code_Coach_Challenge
{
class Program
{
static void Main(string[] args)
{
Draw pencil = new Draw();
Draw brush = new Brush();
Draw spray = new Spray();

pencil.StartDraw();
brush.StartDraw();
spray.StartDraw();

}
}

/*
Draw => "Using pencil"
Brush => "Using brush"
Spray => "Using spray"
*/

public interface IDraw
{
void StartDraw();
}

class Draw : IDraw
{
public virtual void StartDraw()
{
Console.WriteLine("Using pencil");
}
}

//hereda esta clase de la clase Draw
clase Brush: Draw
{
//implementa el método StartDraw()
public override void StartDraw(){
Console.WriteLine ("Using brush");
}

}

//hereda esta clase de la clase Draw
clase Spray: Draw
{
//implementa el método StartDraw()
public override void StartDraw(){
Console.WriteLine ("Using spray");
}

}
}

Answer 1

Spelling mistakes in line:43, 53 in class,.. You wrote it as clase