// Learning Processing
  // Daniel Shiffman
  // http://www.learningprocessing.com
  
  // Example 10-2: Bouncing ball class
  
  // Two ball variables
  Ball ball1;
  Ball ball2;
  
  void setup() {
    size(400,400);
    smooth();
    
    // Initialize balls
    ball1 = new Ball(64);
    ball2 = new Ball(32);
  }
  
  void draw() {
    background(255);
    
    // Move and display balls
    ball1.move();
    ball2.move();
    ball1.display();
    ball2.display();
  }