createCanvas(windowWidth, windowHeight);

}

​

function draw() {

  background(220);

  pattern(width/2, height/2, width/3);

}

​

function pattern(x, y, len){

  if(len > 1){

    line(x-len, y-len, x+len, y+len);

    line(x-len, y+len, x+len, y-len);

    circle(x, y, len);

    len /= 2;

    pattern(x, y+len, len);

    pattern(x-len, y-len, len);

  }

}