(1) The plates constituting the licence plates shall be fixed, one on the front of the other on the back of the motor vehicle or trailer, in an upright, position, so that every letter or figure on the plate is upright and easily distinguishable, in the case of the plate placed on the front of the motor vehicle or trailer from in front of the motor or trailer, and in the case of the plate placed on the back, from behind the motor vehicle or trailer.