/** {@inheritDoc} */
 @Override
 public SplitSubHyperplane<Sphere1D> split(final Hyperplane<Sphere1D> hyperplane) {
   final double global = hyperplane.getOffset(((LimitAngle) getHyperplane()).getLocation());
   return (global < -1.0e-10)
       ? new SplitSubHyperplane<Sphere1D>(null, this)
       : new SplitSubHyperplane<Sphere1D>(this, null);
 }
 /** {@inheritDoc} */
 @Override
 public Side side(final Hyperplane<Sphere1D> hyperplane) {
   final double global = hyperplane.getOffset(((LimitAngle) getHyperplane()).getLocation());
   return (global < -1.0e-10) ? Side.MINUS : ((global > 1.0e-10) ? Side.PLUS : Side.HYPER);
 }