The Painted Cave is one of V.M. Straka's other works.
Eric Husch mentions 1) The Painted Cave in relation to the line “this is a city of ancient and flawed geometries.” and suggests a connection to Nazca Lines.
Jennifer Heyward suggests 2) that there is a connection between The Painted Cave and Page 144 of Ship of Theseus (book) as well, but so far none has been found.
This book also is the key to a code in Chapter 5 according to Jennifer Heyward and Eric Husch.