Two answers to the same prompt side by side, and a person's verdict: A is better, a tie, B is better, or both are bad, with the reasons that decided it. Answers stream in their own columns with time, tokens and cost under each; in a blind test the models stay hidden behind A and B until the verdict, then turn over to show who wrote what. Narrow rooms switch between the two instead of squeezing them. (Beamline complete system)