...tangent universe? I don't see how the engine could come from the tangent universe when it is the exact thing that creates it, but in the tangent universe the engine does exist and Donnie sends it back in time. So is there only 1 engine that exists in the tangent universe before the tangent universe is even created, and then sent back in time to the primary universe to create the tangent universe, and then needs to be sent back once again, or does it come from nowhere, but he has to recreate it to let the primary universe continue. It sounds very confusing, but if anyone has opinions please share them!