Flow Field
X-ray · layers
Parameters
How this effect works
Imagine every point on the screen has an invisible arrow pinned to it, each one pointing a slightly different way. Drop a particle anywhere and it simply follows the arrow it happens to be standing on, then the next one, then the next. That is a flow field: the particles have no plan, the field does. Tick Show the field above to make the arrows visible — the particles were obeying them all along.
The arrows come from one line of maths: two sine waves combined into an angle. Nothing is stored, nothing is precomputed — ask the function for any point and it answers with a direction. Field scale zooms this invisible landscape: small values give long lazy rivers, large values give tight turbulence. The trails layer, exactly as in Matrix Rain, is just a translucent wipe instead of a clear — the paths you see are the past refusing to disappear at once.