// Example 10-07 from "Getting Started with Processing" 
// by Reas & Fry. O'Reilly / Make 2010

float[] x = {-20, 20};

void setup() {
  size(240, 120);
  smooth();
  noStroke();
}

void draw() {
  background(0);
  x[0] += 0.5;  // Increase the first element
  x[1] += 0.5;  // Increase the second element
  arc(x[0], 30, 40, 40, 0.52, 5.76);
  arc(x[1], 90, 40, 40, 0.52, 5.76);
}

