Most of the Piazza di San Pietro is actually an oval. There is a small, almost rectangular section immediately in front of the St Peter's and an opening to the Via della Conciliazione opposite the basilica.

St. Peter's Square

The Vatican Obelisk is an Egyptian obelisk, one of the thirteen ancient obelisks of Rome. This obelisk is located in St. Peter's Square, in Vatican City.

https://en.wikipedia.org/wiki/Vatican_obelisk

Vatican Obelisk

This site is the fulcrum of the north colonnade

Centro del Colonato

San Lorenzo

Heart-shaped stone in Saint Peter's Square

Il Cuore di Nerone