No dwelling unit shall hereafter be erected, constructed, placed, altered or enlarged which shall be like or substantially like any neighboring building then in existence or for which a building permit has been issued if said neighboring building is within 600 feet of the building to be erected, constructed, placed, altered or enlarged and faces on the same street. End-to-end reversal of house plans or roofline changes alone shall not render a dwelling unit substantially unlike a neighboring building to allow its construction, placement, alteration or enlargement within the prohibited distance above set forth.