static Int64 lastFrameID = 0;

        static int handID = -1;

        static float timer = 1;         //Initialize a 1 second timer
        static float TIMER = 1;

        #region Second Attempt

        enum States { None, Fist, Opened } ;

        static States storedState = States.None;

        static void SecondAttempt(Frame frame, GameTime gameTime)
        {
            if (frame.Id == lastFrameID || frame.Hands.Count <= 0) return;

            Hand hand;
            bool knownHand = false;

            float elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds;
            timer -= elapsed;

            //if timer expired
            if (timer < 0)
            {
                //Reset Timer and stored values in order to retrieve new ones
                handID = -1;
                storedState = States.None;
                timer = TIMER;
            }

            // get hand: tests purpose only
            // Perhaps choose a hand based on the user's preference => rightmost or leftmost
            if (handID == -1)
                hand = frame.Hands[0];
            else
            {
                knownHand = true;
                hand = frame.Hand(handID);
            }

            // is hand invalid?
            if (!hand.IsValid)
            {
                // Reset values
                // if timer is set to less than 0, then handID and storedState will be set to -1 and States.None respectively, in the next iteration
                timer = -1;
                return;
            }
            else
            {
                handID = hand.Id;
            }

            States currentState = isLeapHandFist(hand) ? States.Fist : States.Opened;

            // (storedState != States.None && storedState != currentState)
            bool detectedChange = (storedState != States.None && storedState != currentState);//((storedState == States.Fist && currentState == States.Opened) || (storedState == States.Opened && currentState == States.Fist));

            if (knownHand && timer < TIMER && detectedChange) // if changed from a state to another in the interval set
            {
                if (currentState == States.Opened)
                    Console.WriteLine("Detected opening gesture");
                else
                    Console.WriteLine("Detected closing gesture");

                timer = -1;
            }
            else if (!knownHand)
            {
                // Update stored state
                storedState = currentState;
            }

            lastFrameID = frame.Id;
        }

        static bool isLeapHandFist(Hand leapHand)
        {
            if (leapHand.Fingers.Count > 1)
                return false;

            Vector handXBasis = leapHand.PalmNormal.Cross(leapHand.Direction).Normalized;
            Vector handYBasis = -leapHand.PalmNormal;
            Vector handZBasis = -leapHand.Direction;
            Vector handOrigin = leapHand.PalmPosition;

            Leap.Matrix handTransform = new Leap.Matrix(handXBasis, handYBasis, handZBasis, handOrigin);
            handTransform = handTransform.RigidInverse();

            Vector transformedPosition = handTransform.TransformPoint(leapHand.SphereCenter);

            float sphereCenterOffset = transformedPosition.z;

            if (sphereCenterOffset > 0 || (leapHand.SphereRadius < 90 && sphereCenterOffset > -26 && sphereCenterOffset <= -21) ||
                (leapHand.SphereRadius < 75 && sphereCenterOffset > -21 && sphereCenterOffset <= -15) ||
                (leapHand.SphereRadius < 87 && sphereCenterOffset > -15 && sphereCenterOffset <= -10) ||
                (leapHand.SphereRadius < 110 && sphereCenterOffset > -10))
            {
                //Console.WriteLine("Closed Fist");
                return true;
            }
            else
            {
                //Console.WriteLine("Open Hand");
                return false;
            }
        }

        #endregion