float theta = 0;
float delta = 0.05;
int depthLimit = 8;
float scaleFactor = 0.6;

void setup() {
  size(512, 512);
  frameRate(30);
  smooth();
}

void draw() {
  background(255);

  rectMode(CENTER);
  noStroke();
  
  translate(mouseX, mouseY);
  rotate(theta);
  
  drawPlanet(0);
  
  theta += delta;
    
}

void drawPlanet(int depth) {
  
  if (depth > depthLimit) {
    return;
  }
  
  fill(240, depth*32, depth*32);
  rect(0, 0, 90, 90);
  
  pushMatrix();
  translate(-120, 0);
  scale(scaleFactor);
  rotate(theta);
  drawPlanet(depth+1);
  popMatrix();
  
  pushMatrix();  
  translate(120, 0);
  scale(scaleFactor);
  rotate(theta);
  drawPlanet(depth+1);
  popMatrix();
  
}