// Learning Processing
  // Daniel Shiffman
  // http://www.learningprocessing.com
  
  // Example 17-7: Boxes along a curve 
  
  PFont f;
  
  // The radius of a circle
  float r = 100;
  
  // The width and height of the boxes
  float w = 40;
  float h = 40;
  
  void setup() {
    size(320,320);
    smooth();
  }
  
  void draw() {
    background(255);
    
    // Start in the center and draw the circle
    translate(width/2, height/2);
    noFill();
    stroke(0);
    // Our curve is a circle with radius r in the center of the window.
    ellipse(0, 0, r*2, r*2); 
    // 10 boxes along the curve
    int totalBoxes = 10;
    // We must keep track of our position along the curve
    float arclength = 0;
    // For every box
    for (int i = 0; i < totalBoxes; i ++ ) {
      // Each box is centered so we move half the width
      arclength += w/2; 
      
      // Angle in radians is the arclength divided by the radius
      float theta = arclength / r;
      
      pushMatrix();
      // Polar to cartesian coordinate conversion
      translate(r*cos(theta) , r*sin(theta));
      // Rotate the box
      rotate(theta);
      
      // Display the box
      fill(0, 100);
      rectMode(CENTER);
      rect(0, 0, w, h);
      popMatrix();
      
      // Move halfway again
      arclength += w/2;
    }
  }