TSUCS — dx/dt = a·(y − x) + d·x·z, dy/dt = b·x − x·z + f·y, dz/dt = c·z + x·y − e·x². Classic a=40 b=55 c=1.833 d=0.16 e=0.65 f=20 (Lü–Chen–Cheng / Li). Dual a+d sliders; b,c,e,f fixed. Distinct from lorenz.html, lu.html, chen.html, diffusionless-lorenz.html, pham.html. Bulk centroid ≈ (6.4009, 13.2819, 2.2980). RK4 three-scroll fold. Gold low-alpha trail, cap 650. RM = settled silhouette, no animate-on.