Switch between three nonlinear rule sets — all derived from the same kernel.
each cell per tick:
1. diffuse I (slow), R (fast), A (medium)
2. A += κ·(Ī·R̄) ← kernel row [1,1,0,0]
3. if A > θ_fire: ← nonlinear threshold
fire = true
I -= α·I ← rewrite consumes invariant
R += β·(1-R) ← asymmetry grows
S = clamp(S+γ,0,1) ← closure records event
A -= θ_fire ← reset (refractory)
4. if proj ON: normalise ΣI
Firing is the discrete rewrite step: U(K) applied once. Because U(K)²=0, a fired cell cannot immediately re-fire — it must recover through diffusion first.