class Poly {
  ArrayList v;
  Poly() {
    v = new ArrayList();
  }
  
  void add_point(float x, float y) {
    v.add(new PVector(x,y)); 
  }
  
  void render() {
    for (int i = v.size()-1; i >= 0; i--) {
      PVector p = (PVector) v.get(i);
      ellipse(p.x,p.y,20,20);
    }
  }
}