∅ kept the card with the fish, kept it where he’d found it, under the edge of the tatami, but tucked a bit further in so that it did not show past the edge. He retrieved it in the evenings, when he got in bed, and studied it, turning it over between thumb and forefinger, watching the design evolve on the one side, noting that it neither seemed to repeat nor to run to fixation, a pure color field, but maintained a pleasing complexity and broken symmetry. Now and then the state parameters seemed to shift—the movements of the pattern elements, the wave fronts and pulsations, sped up or slowed down, the self-symmetric curves got smoother or more fractal-like, the motif switched from tree rings to waves to loops to darting gliders. It was responsive to sound as well as pressure, with beats producing the stone-tossed-in-the-lake effect at what appeared to be random positions across the surface of the card and clicks producing a kind of glitch, random noise all over the image. The topology, he saw, was periodic—you could bring the edges together along either axis and the design would be continuous. ∅ took a professional interest in all this. Whoever had implemented this had known what she, he, they were doing. The other side appeared to have no responsiveness, no animacy. It was simply an ink brush drawing of a fish on a line. He spent a few minutes with it every night before turning off the lights but apart from that did not make much of it.