let blink = 0;

​

function setup() {

  createCanvas(500, 400);

}

​

function draw() {

  background(115, 130, 170);

  blink++;

  rectMode(CENTER);

  if (blink < 50) {

    rect(width / 2, height / 2, 100, 100);

  }

​

  if (blink == 80) {

    blink = 0;

  }

}

​