Nanorobots embedded in a painting or sculpture don't need a central computer to look "alive" — a swarm of simple electrochromic units that only sense their own pigment and a diffusing neighbor signal is enough to generate ever-changing color and relief patterns entirely from local rules. This simulator renders a grid of nanobots as an interactive 3D relief driven by a real Gray–Scott reaction–diffusion system: each cell's color and height respond only to its own activator/inhibitor concentrations, with feed and kill rates you can tune into spot, maze or travelling-wave regimes, and a paint brush that lets you trigger the swarm directly and watch the stimulus propagate and evolve on its own, the same self-organizing mechanism proposed for interactive nanorobot art installations and adaptive, self-healing "living paintings."