Take box X with device inside, place on scale it weights 21lbs. Turn device inside box on, it now weights 4 lbs.
Next take box X and turn it upside down on scale it weights 21 lbs. Turn device inside box on, it now weights 38 lbs.
What does this mean?
C.
It means the device in the box is able to create a thrust like force against gravity. When it is upside down, then it enforces gravity by this thrust like force.
Hope you are not pulling our leg... Could you share some more on this device?
rgds, Gyula