/** Reverses the tangents and normals associated with this BSpline */
 public void reverseNormalsAndTangents() {
   for (CubicBezier b : approximationCurves) {
     for (Vector2 p : b.getNormalReferences()) p.mul(-1);
     for (Vector2 p : b.getTangentReferences()) p.mul(-1);
   }
 }
 /**
  * Returns the sequence of normals on this BSpline specified by the sequence of approximation
  * curves
  */
 public ArrayList<Vector2> getTangents() {
   ArrayList<Vector2> returnList = new ArrayList<Vector2>();
   for (CubicBezier b : approximationCurves)
     for (Vector2 p : b.getTangents()) returnList.add(p.clone());
   return returnList;
 }