Lit metallic knot — warm/lime/blue three-point rig, slow tumble.

The only object in the batch shaded by three.js's standard PBR material rather than hand-written GLSL, and it earns the difference: at 0.95 metalness and 0.22 roughness the near-black surface reads almost entirely as reflected light, so the three-point rig does all the work. A warm amber key from upper right, a lime fill from lower left and a cool blue directional from behind separate the knot from the ground. Rotating on two axes at different rates so the highlights sweep the curvature rather than sitting still.