According to Demis Hassabis on X, a demo shows Gemini 3.1 being used as a city builder to generate and iterate virtual urban layouts for simulation-style gameplay, linking natural language prompts to procedural content creation. As reported by Demis Hassabis, the workflow leverages Gemini 3.1’s multimodal reasoning to translate high-level planning instructions into street grids, zoning, and assets, reducing manual mapmaking time. According to the post source, this points to new business opportunities for game studios and simulation software vendors to accelerate level design, run what-if policy experiments, and personalize worlds at scale with generative agents. As noted by Demis Hassabis, integrating Gemini 3.1 with tool-use APIs enables constraint-aware placement (e.g., traffic flow, utilities), suggesting practical applications in urban planning sandboxes, training environments for autonomous agents, and educational city simulators.