Star Forts of New York City

How Many Star Forts existed in the past and how many still exist and the physics behind the building of the star forts. Google Earth and old maps of these forts. At 1776 the star forts were already built since they are on the old maps. Cloisters a part of the Metropolitan Museum of Art and Rockefeller connection to Fort Tryon and Fort Washington. Fort Wood with the Statue of Liberty, Fort Amsterdam in Battery Park ( any name connection with the park?) Fort Gibson on Elis Island , A list of Star Forts found on a New York Encyclopedia.