Brusselator — dx/dt=A−(B+1)·x+x²·y, dy/dt=B·x−x²·y, dz/dt=C·(x−z). Classic A=1 B=3 C=1. Dual B+A sliders; C fixed 1. Display embed (x,y,z). Distinct from operon.html, oregonator.html, willamowski.html, bell.html, hindmarsh-rose.html. Bulk centroid ≈ (0.9987, 3.1717, 1.0005). RK4 chemical limit-cycle. Gold low-alpha trail, cap 650. RM = settled silhouette, no animate-on.