Perspective, with the Reason of Shadows and Mirrors

well understood, without doubt one will be able to give a reason for what one does. Furthermore, I have made the discourse of the figures as brief as I possibly could, begging the kind Reader to have recourse to the figures if the discourse does not provide the intelligence; it is not an easy thing to demonstrate this art by writing. May God keep you.

Before treating of anything, it will not be bad to give the intelligence of the Figures, of which we shall treat hereafter, that is to say to show the form of each particular figure with its name, for the construction of these figures is not needed to be treated here; it is a particular art of which so many learned persons have treated that it would be a superfluity to show any part of it, thus one will be able to learn in these figures their name only.