Willamowski–Rössler — minimal mass-action chemical chaos: dx/dt=x·(a1−k1·x−y−z), dy/dt=y·(−a3+x), dz/dt=z·(a2−x−kz·z). Classic a1=30 a2=16.5 a3=10 k1=0.25 kz=0.5. Dual a1+a2 sliders. Display embed (x,y,z). Distinct from rossler.html, hindmarsh-rose.html, duffing.html, lorenz.html, chua.html. Bulk centroid ≈ (10.0147, 14.5176, 12.9771). RK4 chemical fold. Gold low-alpha trail, cap 650. RM = settled silhouette, no animate-on.