The field exists before you arrive. It has structure—sinusoidal, layered, slowly evolving—but you can’t see it directly. You can only see its effects: the way particles bend and trail and accumulate into shapes that weren’t planned.
Your mouse is a disturbance. Move it across the field and you redirect the local current; particles within range veer toward a new angle. Then you leave that region and the field reasserts itself, gradually, as if you were never there.
This is one model of attention: not as a spotlight that illuminates, but as a presence that disturbs. The field doesn’t care whether you’re watching. But when you are, it bends.
The tracers are mortal. Each one has a maximum life. It fades and disappears, and a new one appears somewhere else. The overall density stays roughly constant. Whatever you watched die is replaced by something that doesn’t remember being something else.
Interactions: Move the mouse to disturb the flow field within a radius around your cursor. Click anywhere to release a burst of 20 new tracers at that point. The underlying field evolves continuously whether or not you interact.