int i, x, y = 0;

void setup() {
  size(640, 480);
  background(0);
  smooth();
}

void draw() {
  if (mousePressed && mouseButton == RIGHT) {
    background(0);
    return;
  }
  if (mousePressed && mouseButton == LEFT) {
    int r = (mouseX % 200) + 55;
    int g = (mouseY % 200) + 55;
    int b = ((mouseX + mouseY) % 200) + 55;
    stroke(r,g,b,1);
    fill(r,g,b,1);
    x = (x + int(random(10))) % 768;
    y = (y - int(random(10))) % 768;
    translate(mouseX,mouseY);
    rotate(radians(i++ % 360));
    ellipse(0,0,x/4,y/4);
  }
}