In November, Perlstein Properties filed applications for a three-story, three-unit residential building at 1668 59th Street, located on the southern end of Borough Park. The same developer recently filed plans for another three-story, three-unit residential building next door at 1670 59th Street. The second building would measure 6,400 square feet and its full-floor residential units should average a family-sized 1,612 square feet apiece. Brooklyn-based Tecnico Engineering is the applicant of record for both structures. Both lots at 1668-1670 59th Street, which measure 6,010 square feet together, are vacant.