Smart cities run their traffic signals, water pumps and power substations over a shared mesh of networked ICS/SCADA controllers — convenient for operators, and also a ready-made path for malware to spread from one compromised device to the next. This simulator models an 8×8 grid of city intersection controllers as a real graph, seeds a worm at one node, and propagates it node-to-node across live communication links using a discrete-time SIR epidemic process. Two real defensive levers are exposed: raising the detection/patch rate to represent a faster SOC response, and toggling network segmentation to cut the backbone links between city districts — the standard OT security practice of breaking a flat network into isolated zones. Live counters track how many controllers are compromised, how many have been patched, and how long the outbreak has been running, so you can see directly how segmentation slows a worm's reach across the city grid.