public override void Remove(DrawingElement c) { Console.WriteLine("Con not remove from PrimitiveElement"); }
public override void Remove(DrawingElement c) { elements.Remove(c); }
public override void Add(DrawingElement c) { Console.WriteLine("Con not add to PrimitiveElement"); }
public abstract void Remove(DrawingElement c);
public override void Add(DrawingElement c) { elements.Add(c); }
public abstract void Add(DrawingElement c);