The spreads in the book are always printed only on the right side. On the blank left pages, however, an indentation of the previous right page is faintly visible throughout the book.
Before 50 representations of doorways are shown, something else is shown on the first three spreads. First, an ornate front page with information about the book appears. The illustration on the next double page has no text and is not an archway. In a vase-shaped frame, among other things, cords, a cross, the head of a lion, a bird and a dragon are depicted. Possibly this drawing is a family crest of the author? The third spread shows an Italian text signed with Bernardino Radi. I can well imagine that this is a preface.