A cellular automaton designed by Brian Silverman. Unlike Conway's Game of Life, cells have three states: Ready (0), Firing (1), and Refractory (2).
A Ready cell turns into a Firing cell if it has exactly two Firing neighbors. A Firing cell immediately transitions to Refractory (Dying) in the next step. A Refractory cell becomes Ready in the next step. This mimics the action potentials in biological neural networks.
The result is a constant churn of diagonal gliders and propagating waves, a pure ALife model of neural excitability.