public static void DrawDemo()
{
DrawingObject[] dObj = new DrawingObject[5];
dObj[0] = new Line1();
dObj[1] = new Line2();
dObj[2] = new Circle();
dObj[3] = new Square();
dObj[4] = new DrawingObject();
foreach (DrawingObject drawObj in dObj)
{
drawObj.Draw();
}
var line1 = new Line1(); // if modifier isn`t be like in base e.g. class method as "protected void Draw()" CLR calling base class method Draw
line1.Draw();
var line2 = new Line2(); // but if modifier declared as protected internal CLR calling derived class method Draw
line2.Draw();
var circle = new Circle();
circle.Draw();
}