let colorMults = [3, 4, 5]

function setup() {

  createCanvas(400, 400);

  ellipseMode(RADIUS);

  rectMode(CENTER);

}

​

function draw() {

  background(220);

  stroke(0);

  noFill();

  side = 5;

  strokeWeight(3);

  for(i = 1;i < 1000; i++){

    stroke(side*colorMults[0]%255, 

           colorMults[1]%255, 

           side*colorMults[2]%255)

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

    ellipse(width/2, height/2, side/2);

    side*=sqrt(2)

  }

}