let bgndColor;

​

function setup() {

  createCanvas(windowWidth, windowHeight);

  lastUpdate = millis();

  bgndColor = color(220, 10, 120);

}

​

function draw() {

  if (millis() - lastUpdate > 1000) {

    bgndColor = color(random(180, 250), random(0, 50), random(90, 150));

    lastUpdate = millis();

  }

​

  background(bgndColor);

}

​