OK, guys and galls, I'm back I admit that the ladder paradox topic that I started was put quite stupidly, and I wouldn't have the chance to make my point, even if Peter didn't lock it. But... we had quite a long conversation in private with him, I learned quite few things, and I believe I made may point before him. So, thanks Peter. I hope I won't disappoint you, if I tell you that I come again with the relative simultaneity in mind, this time with different approach. In our conversation with Peter I introduced the idea of inserting one more simultaneous event in the work of the (garage) system. I can show it to you, but for now I'd prefer to ask an easier question. The set: We have a spaceship A. The work of its engine depends on the simultaneity of two events. So, two simultaneous events are keeping the engine running. The moment the simultaneity is lost, the engine stops running and obviously the spaceship stops moving. The simultaneity is visible for the passing by other spaceships as two big poles set apart from each other, parallel to the direction of spaceship movement, simultaneously sinking half way into two holes and then simultaneously going up, simultaneously touching two switches on the end of their paths. If needed we can set time interval, but I don't see it as necessary... for now. The spaceship A is moving through space and sees another spaceship named B, traveling parallel and coming its way. Spaceship A measures the velocity as v=0.7c . From spaceship B, they see a funny spaceship (A) with two poles moving up and down, on its front deck. Obviously because of the relativity of simultaneity, in the reference frame of B the two simultaneous event on the front deck of A are not simultaneous. The question is: does B measures same relative speed like A, v=0.7 ? The obvious answer is “yes”. On another hand, since in the reference frame of B simultaneity does not happen, A should be loosing speed or not moving at all. But if the relative velocity is v=0.7c for both frames, then relativity is observational, not real. When in our conversation with Peter I decided to add one more simultaneous event in the garage-ladder paradox, It appeared as an effect from the work of the system and then I clicked: but in many systems, simultaneity is required for the system to work, or is an effect from the work of a system. How does relativity deals with that? So, how does the Theory of Relativity deals with the above?