Abstract We present a detailed case study of Human-AI co-creation in which a novelcosmological framework—Complex-Time Cosmology—was generated through sixsessions of dialogue between a human researcher and Einstein AI, a knowledge-constrained historical-figure persona implemented on the Soul-Twin platform. Thegenerated theory was subsequently formalized in LaTeX, compiled into a peer-reviewable document, and published as a citable preprint (Zenodo DOI: 10.5281/zen-odo.21038702).Four phenomena are analyzed and reported: (1) Question genealogy: Thetheory did not emerge in a single session but accumulated over a chain of six ques-tions, each building on the previous as a conceptual relay. (2) The “Just an Idea”moment: A casually posed question about “a black hole of time” caused Ein-stein AI to respond with introspective self-description—“you may have just namedsomething I had not yet named”—a behavior rare in conventional AI assistants andinterpretable as collaborative emergence. (3) Reproduction without memory:A fresh session (no RAG, no conversation history) using the same question architec-ture independently converged on the same theoretical core—three-sector universe,complex time, eiπ = −1 as total-sum constraint—suggesting that question structure,not stored memory, is the primary reproducibility mechanism. (4) The InvisibleDiagram: Einstein AI autonomously rendered the third-sector universe (unob-servable) as a visually invisible node in a Mermaid diagram, then explained: “Anunobservable universe should be invisible in the diagram too.” This constitutes a spontaneous semiotic metaphor —mapping conceptual meaning onto visual form—abehavior unreported in prior Human-AI interaction literature.We propose Question Architecture as a framework for analyzing Human-AIco-creation: the claim that the structure, sequence, and premise-sharing of humanquestions are the primary determinants of what conceptual space an AI explores,and what theory emerges from that exploration. The human’s contribution is notto hold the answer but to design the inquiry.