let color_list = []

function setup() {

  createCanvas(400, 400);

}

​

function xmark() {

  square(frameCount, frameCount, 50);

  square(frameCount, 350 - frameCount, 50);

}

​

function flshcircle() {

  circle(200, 200, 75)

  fill(colour)

}

​

function draw() {

  color_list = ['red', 'blue']

  colour = color_list[random(0, 1)]

  xmark();

  flshcircle();

}

​