function setup() {
  createCanvas(200, 200);
  noLoop();
}

function draw() {
  background(0);
  stroke(255);
  strokeWeight(5);
  beginShape(POINTS);
  for (let i = 0; i < 100; i = i + 10) {
    vertex(50 + random(-3, 3), 50 + i);
    vertex(50 + i, 150 + random(-3, 3));
    vertex(150 + random(-3, 3), 150 - i);
    vertex(150 - i, 50 + random(-3, 3));
  }
  endShape(CLOSE);
}