public void draw() {
    // background(255);
    fill(255);
    rect(-4, -4, width + 4, height + 4);

    for (int i = skaters.size() - 1; i >= 0; i--) {

      Skater skater = (Skater) skaters.get(i);

      // if (mousePressed) {
      skater.trace(mouseX, mouseY); // blob[i].x etc.

      println(i);
    }
  }
 protected String getSkaterNumber(Skater s) {
   return (null == s ? NO_SKATER_NUMBER_VALUE : s.getNumber());
 }
 protected String getSkaterName(Skater s) {
   return (null == s ? NO_SKATER_NAME_VALUE : s.getName());
 }