code: public Matrix4f reflect(float nx, float ny, float nz, float px, float py, float pz) {
          return reflect(nx, ny, nz, px, py, pz, thisOrNew());
      }
docs: Apply a mirror/reflection transformation to this matrix that reflects about the given plane
  specified via the plane normal and a point on the plane.
  <p>
  If <code>M</code> is <code>this</code> matrix and <code>R</code> the reflection matrix,
  then the new matrix will be <code>M * R</code>. So when transforming a
  vector <code>v</code> with the new matrix by using <code>M * R * v</code>, the
  reflection will be applied first!
  
  @param nx
  the x-coordinate of the plane normal
  @param ny
  the y-coordinate of the plane normal
  @param nz
  the z-coordinate of the plane normal
  @param px
  the x-coordinate of a point on the plane
  @param py
  the y-coordinate of a point on the plane
  @param pz
  the z-coordinate of a point on the plane
  @return a matrix holding the result