class Tracer{
  Vec2 [] vector;
  boolean first = true;
  Tracer(){
    vector = new Vec2[1];
    vector[0] = new Vec2();
  }
  void trace(Vec2 add){
    int num;
    if (first){
      vector[0] = add;
      first = false;
    }
    else{
      vector = addVector(vector, add);
    }
  }
  void draw(){
    stroke(0,0,0,155);
    for(int i = 0; i < vector.length; i++){
      fill(0,0,0,100);
      ellipse(vector[i].x*width,vector[i].y*height,20,20);
      fill(0);
      text(i,vector[i].x*width,vector[i].y*height);
    }
    fill(0,0,0,20);
    beginShape(POLYGON);
    for(int i = 0; i < vector.length; i++){
      vertex(vector[i].x*width,vector[i].y*height);
      }
    endShape();
  }
  double [] xVectors(){
    double [] x = new double[vector.length];
    for(int i = 0; i < vector.length; i++)
      x[i] = (double)(vector[i].x);
    return x;
  }
  double [] yVectors(){
    double [] y = new double[vector.length];
    for(int i = 0; i < vector.length; i++)
      y[i] = (double)(vector[i].y);
    return y;
  }
}