Lü — dx/dt = a·(y − x), dy/dt = −x·z + c·y, dz/dt = x·y − b·z. Classic Lü–Chen 3D ODE (a=36, b=3, c=20). RK4, not Chen ((c−a)·x − x·z + c·y), not Lorenz butterfly, not four-wing Qi, not Dadras, not Sprott Case A, not Halvorsen, not Chua, not Aizawa, not Thomas, not Rössler. Gold low-alpha trail, cap 650. RM = settled silhouette, no animate-on.