Liu–Chen chaotic system — dx/dt = a·x − y·z, dy/dt = −b·y + x·z, dz/dt = −c·z + x·y with c=3.6 fixed. Classic a=5 b=10. Dual a+b sliders. Distinct from liu.html (Liu 2004 a(y−x)/bx−xz/−cz+xy), zhou.html, chen.html, chen-celikovsky.html, chen-lee.html, lu.html. Bulk centroid ≈ (0.0202, -0.0040, 5.2060). RK4 Liu–Chen fold. Gold low-alpha trail, cap 650. RM = settled silhouette, no animate-on.