let b = []

let c = []

let d = []

function setup() {

  createCanvas(400, 400);

  background(220);

  strokeWeight(2);

  stroke(0,255,255);

  for (let i = 0; i < 100; i++) {

    a.push(random(0,2 * PI))

    b.push([-1,1][round(random(1))])

    c.push(random(20,200))

    d.push(createVector(200,200))

  }

}

​

function draw() {

  fill(0,0,0,5);

  rect(0,0,width,height);

  for (let i = 0; i < 100; i++) {

    a[i] = a[i] + PI / 100 * b[i]

    x = d[i].x + c[i] * cos(a[i])

    y = d[i].x + c[i] * sin(a[i])

    point(x,y)

  }

}