Sprott Case A — dx/dt = y, dy/dt = −x + y·z, dz/dt = a − y². Simplest dissipative chaotic 3D flow. RK4, not Halvorsen cyclic quadratic, not Chua circuit, not Aizawa sphere, not Thomas cyclic sin, not Rössler fold, not Lorenz butterfly. Gold low-alpha trail, cap 650. RM = settled silhouette, no animate-on.