As the two signals travel through space, the distance between each signal gets greater over time the signal travels. Both signals are the same and one day alien species XYZ comes across one and then discoveries the same signal 1,000 light years away. Fascinated, the alien species begins to work the signal back to its location based on the distance between both signals reducing until the a point when the signals are are very strong and less than 1 light year in distance. Just like cattle in a funnel chute, at first the aliens will turn and twist trying to make an escape if you will, but as the chute gets narrower the thoughts of the cattle and aliens would be more aligned with what was in front of it due to the chutes or signals on both sides not allowing the cow to turn around very easily.