Flow

let agents = [];

const agentCount = 3000;

const cycle = 500;

const step = 5;

​

class Agent {

  constructor() {

    this.x = random(width);

    this.y = random(height);

    let n = this.x + this.y - 2 * frameCount;

    let rem = ((n % cycle) + cycle) % cycle;

    this.color = rem < cycle / 2 ? "black" : "white";

  }

  update() {

    let angle = noise(this.x / width, this.y / height) * 100;

    stroke(this.color);

    line(

      this.x,

      this.y,

      (this.x += cos(angle) * step),

      (this.y += sin(angle) * step)

    );

  }

}

​

function setup() {

  createCanvas(windowWidth, windowHeight);

}

​

function draw() {

  while (agents.length < agentCount) {

    agents.push(new Agent());

  }

  agents.forEach((a) => a.update());

  agents = agents.filter(

    (a) => random(5) > 1 && a.x > 0 && a.y > 0 && a.x < width && a.y < height

  );

}