OL_EhrensteinIllusion

function setup() {
  createCanvas(400, 400);
  noFill()
  rectMode(CENTER);
  strokeWeight(2);//line thickness
}
function draw() {
  translate(200,200)//center at origin
  circleSet()//draw circles
   strokeWeight(3)
  rect(0,0,250,250)//draw square
}
function circleSet(){
  strokeWeight(1)
  for (let i=0;i<20;i++){
    circle(0,0,20+i*20)
  }
}