Lumen sequitur
Five solids that give back nothing of themselves until the cursor lights them, and the light arrives a beat after you do.
Move the cursor. The solids are inert and nearly invisible — a flat #191919 against the void — and the cursor carries the only light in the scene. Nothing is revealed except where you happen to be looking.
The light is late on purpose. It trails the pointer through a critically damped spring, so you are always slightly ahead of what you can see: stop moving and the scene resolves, keep moving and it never quite does. Move faster and the light hardens; press and hold and it comes toward you, tightening every highlight.
Leave it alone for six seconds and it takes the frame back, walking a slow path of its own until you return.
WebGPU only, and honestly so: where WebGPU is missing the page shows the rendered still rather than a black rectangle. No camera, and nothing leaves the machine.