Consider the following statements: 1. If you move relative to me with velocity V I move relative to you with velocity -V. Consider that I am equipped with a machine gun and with a laser gun at rest relative to me and you are equipped with identical machine gun and laser gun at rest relative to you. We are in relative motion with constant speed. If I measure the speed of the light emitted by my laser gun and the speed of a bullet fired by my machined I obtain c and u respectively. If you measure the speed of the light emitted by your laser gun and the speed of the bullet fired by your machine gun you will obtain c and u as well. Would Galileo o.k. the two statements. If yes I will continue.