// Learning Processing
  // Daniel Shiffman
  // http://www.learningprocessing.com
  
  // Example 14-14: Rotating both squares
  
  float theta1 = 0;
  float theta2 = 0;
  
  void setup() {
    size(200,200,P3D);
  }
  
  void draw() {
    background(255);
    stroke(0);
    fill(175);
    rectMode(CENTER);
    
    // Save the current transformation matrix. 
    // This is where we started, with (0,0) in the top left corner of the window and no rotation.
    pushMatrix(); 
    
    // Translate and rotate the first rectangle.
    translate(50,50); 
    rotateZ(theta1);
    // Display the first rectangle.
    rect(0,0,60,60); 
    // Restore matrix from Step 1 so that it isn't affected by Steps 2 and 3!
    popMatrix(); 
    
    pushMatrix();
    // Translate and rotate the second rectangle.
    translate(150,150); 
    rotateY(theta2);
    // Display the second rectangle.
    rect(0,0,60,60); 
    popMatrix();
    
    theta1 += 0.02;
    theta2 += 0.02;
  }