Cornell's patent has a diagram of square glass panes, but as honeybees discovered long ago, hexagons provide a much stronger framework. Notice also Cornell does not use metal studs around each glass lens tp protect the glass, rather there is a raised ridge between them. Alas the metal studs are part of the Thaddeus Hyatt patent of 1845 ( see related cover below)
Former coal hole cover and vault light, now street level celebrity.
This cover is on Henry St. near the corner of Pineapple in Brooklyn Heights. It is unique.