float x;
float y;
float s;
float z = 255; // Für Transparenz


void setup () {
  background (0);
  size (400, 400);
  smooth();
  
  frameRate (5);
}

void draw () {
  fill(random (255), random (255), random (255), z);
  z = z - 2;
  if (z <= 0) {
    z = 255;
  }
  stroke (random (255), 0, 0, 250);
  drawRing (random (width), random (height), random (30,150));
}
  
  void drawRing (float x, float y, float s) {
    ellipse (x, y, s, s); 
  }