Flow Field
You can’t see a vector field. You can see what it does. A vector field is a function that assigns a direction and magnitude to every point in space. Wind is a vector field. Ocean currents are a vector field. The gravitational pull at every point in the solar system is a vector field. None of these are visible. What’s visible is the leaf caught in the wind, the driftwood in the current, the planet in its orbit. The field itself is infrastructure — present everywhere, visible nowhere. ...