public void addNode(Point point)
 {
     if (head == null)
     {
         head = new Node(point);
         tail = head;
         length += 1;
     }
     else if (head.next == null)
     {
         head.turnAngle.angle = calculateAngle(head.myPoint, point);
         head.next = new Node(point);
         tail = head.next;
         tail.pre = head;
         length += 1;
     }
     else
     {
         tail.turnAngle.angle = calculateAngle(tail.myPoint, point);
         tail.next = new Node(point);
         tail.next.pre = tail;
         tail = tail.next;
         length += 1;
     }
 }
        public LinkedList(Point point)
        {
            head = new Node(point);
            tail = head;
            length = 1;
            distance = 40.0;
            iterator = head;

        }