size(300,300);
  background(0);
  noStroke();
  smooth();

for (float a = random(33); a < 300; a += random(13,66)) {
  for (float b = random(267,300); b > 1; b -= random(13,66)) {
    fill(a,30);
    ellipse(b, b%a, a, a%b);
   }
}