docs: public void normalize() {
          double lenSqr = x * x + y * y + z * z;
          double err = lenSqr - 1;
          if (err > (2 * DOUBLE_PREC) || err < -(2 * DOUBLE_PREC)) {
              double len = Math.sqrt(lenSqr);
              x /= len;
              y /= len;
              z /= len;
          }
      }