code: public static boolean isSquarePlanar(IAtom atomA, IAtom atomB, IAtom atomC, IAtom atomD) {
          Point3d pointA = atomA.getPoint3d();
          Point3d pointB = atomB.getPoint3d();
          Point3d pointC = atomC.getPoint3d();
          Point3d pointD = atomD.getPoint3d();
  
          return isSquarePlanar(pointA, pointB, pointC, pointD);
      }
docs: Checks these four atoms for square planarity.
  
  @param atomA an atom in the plane
  @param atomB an atom in the plane
  @param atomC an atom in the plane
  @param atomD an atom in the plane
  @return true if all the atoms are in the same plane