// https://www.w3schools.com/js/js_timing.asp

​

// TEST setTimeout(function, millis)  or  setInterval(function, millis)

let donow = false;

let dt = 3000;

let rr;

let ang = 0;

​

function setup() {

  createCanvas(400, 400);

  print("set timer " + dt);

  setTimeout(start, dt);

  rectMode(CENTER);

  fill(200, 0, 0); //for timeshow

}

​

function draw() {

  background(200, 200, 0);

  noStroke();

  text(nf(millis() / 1000, 1, 1), 10, 20);

  translate(width / 2, height / 2);

  ang += 0.01;

  rotate(ang);

  if (donow) draw_rect();

}

​

function start() {

  print("start");

  donow = true;

  rr = 200;

}

​

function draw_rect() {

  stroke(0, 200, 0);

  strokeWeight(10);

  fill(0, 200, 200);

  rect(0, 0, rr, rr);

  rr--;

  fill(0, 0, 200);   // for timeshow while timer NOT running

  if (rr < 3) {

    donow = false;

    setTimeout(start, dt);

    print("restart timer " + dt);

    fill(200, 0, 0); // for timeshow while timer running

    //ang = 0;

  }

}