Hodgepodge Machine

An excitable cellular automaton (Gerhardt & Schuster 1989) that spontaneously forms spiral waves, similar to the Belousov-Zhabotinsky chemical reaction.

Parameters

Update Rule

if s=0:
a=sick nbrs
b=ill nbrs
s'=⌊a/k₁+b/k₂⌋

if 0<s<k:
s'=avg(nbrs)+g

if s=k:
s'=0 (recover)

Emergence

Spiral waves emerge from random initial conditions — no central pacemaker needed. Analogous to cardiac arrhythmias and the BZ reaction.