docs: private static boolean parallelSideEffectSameX(
              final double pXA, final double pYA, final double pXB, final double pYB,
              final double pXC, final double pYC, final double pXD, final double pYD,
              final PointL pIntersection
      ) {
          if (pXA != pXB) {
              return false;
          }
          if (pXC != pXD) {
              return false; // cannot be parallel
          }
          if (pXA != pXC) {
              return false; // not the same x
          }
          final double yi = middle(pYA, pYB, pYC, pYD);
          return check(pXA, pYA, pXB, pYB, pXC, pYC, pXD, pYD, pIntersection, pXA, yi);
      }