: Visual artists during the Renaissance accidentally birthed projective geometry while trying to realistically map three-dimensional space onto a flat canvas.

The book is divided into 25 chapters, so there is no Chapter 28. This indicates that "28" is not a structural element of the printed book. Instead, it is almost certainly a reference to an online file source, where the number has been appended to the filename as a label, download ID, or page number by a specific website or user. This is a common practice for organizing files but is not an official part of the book's metadata.