La Pratica di prospettiua https://archive.org/details/HArteR08T16/page/n11/mode/2up
This spread is fairly at the beginning, right after the table of contents. On the left side id shows up writing errors and the respective correction, which i found rather interesting. I have never seen something in this form in a book. On the right side of the spread chapter 1 begins with an overview of basic angles and shapes. Also that it starts with a basic level of information caught my attention to this spread. The right page reminds me of a kids geometry book where they learn all shapes for the first time.
This spread is part of the LIBRO PRIMO which translates from italian to “first book” (i asked google). It seemed like all spreads in the libro primo looked like this: text on the left side, corresponding picture on the right. This spread seems to be about arches since the word “archis” appears multiple times in the text and theres obviously a drawing of an arch on the right. Whats interesting about the drawing is that theres lots of parts of the arch marked with letters, which are being referred to in the text. Thus I understand it to be an in depth breakdown of the arch construction, going through nearly every angle and corner of the drawing.
This spread can be found in the LIBRO SECONDO, which probably translates to second(ary?) book. Also here there seems to be a consistent layout throughout the book, being blank pages on the left and very detailed and actually very very gorgeous drawings on the right. I chose this example because im very into corinthian capitals. The drawing itself is made with great attention to detail and very clean as well. However since the book probably hasnt been opened for a very long time, the picture has been imprinted on the left page of the spread, which leads to the same drawing being mirrored onto the left side. This also happened on the other drawing in the libro secondo. It seems like the author knew that this eventually would happen and left the left page empty on purpose.