Move a light and see a tiny simulated creature steer toward it—or flee. Aatish Bhatia and neuroscientist Arkarup Banerjee’s Myriad explainer builds the behavior from sensory neurons, motor neurons and two connections.

Cross the wires and the steering changes. Switch from excitation to inhibition and the creature can slow down near its target. It is a clear introduction to how a simple artificial neural controller produces behavior.

These circuits are fixed: the creatures do not learn in this chapter. The authors draw on Valentino Braitenberg’s 1984 thought experiments, using deliberately simplified simulations rather than claiming to reproduce a real brain.