The Secret Symbols of the Rosicrucians of the 16th and 17th Centuries is a book published by the Rosicrucian Order, edited by H. Spencer Lewis. It contains (among others) reproductions of Rosicrucian charts and symbols from the above era. The 21st diagram of the first part of the book (seen to the right) visibly served as an inspiration for the Plane chart, a diagram describing the hierarchy of the mazoku in the worlds created by the Lord of Nightmares. Two symbols in particular, the one in the