An excitable-medium cellular automaton approximating the oscillating BZ
chemical reaction. Resting cells ignite when enough excited neighbors
are present; excited cells become refractory, then rest — generating
self-organizing spiral waves.
Click on the canvas to plant a spark
0
Generation
–
Excited cells %
0
Sparks planted
Grid size180
Excite threshold2
Refractory steps3
Spontan. rate4 / 100k
Sim speed3
Belousov-Zhabotinsky (BZ) reaction (1951/1961) is a
classic example of non-equilibrium self-organization: a mixture of
malonic acid, bromate and a metal catalyst spontaneously oscillates
between oxidized and reduced states, producing colour waves visible with
the naked eye. This simulation uses a
3-state excitable-medium CA (Greenberg-Hastings model):
🟡 Excited (state 1): becomes refractory on next
step.
🔴 Refractory (states 2…k): counts down to resting.
⚫ Resting (state 0): ignites if ≥ threshold excited
Moore neighbors exist.