public override void OnItemPlaced(List <UndoRedoAction> undoPipe)
{
lock (board.ParentControl)
{
base.OnItemPlaced(undoPipe);
PointA.OnItemPlaced(undoPipe);
PointB.OnItemPlaced(undoPipe);
PointC.OnItemPlaced(undoPipe);
PointD.OnItemPlaced(undoPipe);
}
}