How are you deciding which resistors are the "diagonal" resistors? Per her diagram, the diagonal resistors would be between A & C and between B & D.Even without doing any derivations, one can tell that the diagonal resistors are low valued and the side resistors are high valued - with approximately two orders of magnitude between the values. Assuming that the side resistors are infinite, then the diagonal resistors are each 11.4 ohms. Assuming that the diagonal resistors are zero, then the side resistors are each 2000 ohms. I think a more accurate guess for the side resistors would be 2000 minus twice the diagonal resistance yielding 1977 ohms.