public interface IVisible {
	bool Visible { get; set; }
}

public class Customer : IVisible {
public Customer() {
	this.Visible = true;
}

public string Name { get; set; }
public int Age { get; set; }
public bool Visible { get; set; }

public override string ToString() {
	return String.Format("{0} je star/star {1} let.", Name, Age);
}
}
