The circle, the daisy wheel, governs the design and frame for the Old First Church.
The circle was often used for the top of the window in the 19th century as well as just for decoration.
The posts in this series Lessons 1-7 are :
https://www.jgrarchitect.com/2020/04/lessons.html
https://www.jgrarchitect.com/2020/04/practical-geometry-lessons-2.html
https://www.jgrarchitect.com/2020/04/practical-geometry-lesson-3.html
https://www.jgrarchitect.com/2020/04/practical-geometry-lesson-4.html
https://www.jgrarchitect.com/2020/04/practical-geometry-lesson-4b-old-first.html
https://www.jgrarchitect.com/2020/06/practical-geometry-lessons-lesson-5.html
https://www.jgrarchitect.com/2020/06/practical-geometry-lesson-5-addendum.html
https://www.jgrarchitect.com/2020/08/lesson-6-rule-of-thirds-part-1_21.html