let x = 1, y = 1;

  if(t > 0.75) {

    y = -1;

    t = 1 - t;

  }

  else if(t > 0.5) {

    x = -1;

    y = -1;

    t = t - 0.5;

  }

  else if(t > 0.25) {

    x = -1;

    t = 0.5 - t;

  }

  t = t * 2;

  x *= 5 / (t*t + 1) - 4;

  t = t - 0.5;

  y *= 5 / (t*t + 1) - 4;

  return [x, y];

}

​

function setup() {

  createCanvas(400, 400);

  background(220);

}

​

function draw() {

  let t = random();

  let [x, y] = circle_pt(t);

  point( width/2  + 150*x, 

         height/2 - 150*y);

  if(frameCount > 100) noLoop();

}

​

​