The fantastic Jesuit Andrea Pozzo published results of his researches on perspective in his Perspectiva pictorum et architectoru (1693), explaining how he was able to compellingly, unbelievably represent three-dimensional images on two-dimensional spaces, this image showing plan and projection and profile, effectively giving you a three-dimensional cross section of the architectural element...and having them seemingly float in space. His work is just absolutely gorgeous.
The full title: Rules and examples of perspective proper for painters and architects, etc. in English and Latin, containing a most easie and expeditious method to delineate in perspective all designs relating to architecture, after a new manner, wholly free from the confusion of occult lines /‡cby that great master thereof, Andrea Pozzo, Soc. Jef. engraven in 105 ample folio plates, and adorn'd with 200 initial letters to the explanatory discourses ; printed from copper-plates ony best paper by John Sturt ; done into English from the original printed at Rome 1693 in Lat. and Ital. by Mr John James of Greenwich (1693)