createCanvas(400, 400);

}

​

function draw() {

  background("red");

  let timeInMilliseconds = millis();

  if (timeInMilliseconds > 4000) {

    // if more than 4 seconds have passed

    background("green");

  } else if (timeInMilliseconds > 2000) {

    // otherwise if more than 2 seconds have passed

    background("blue");

  }

}