... like a knot tied in a rope

"Whereas the intellect reproduces species by attracting likenesses from physical and imaginable things to its coessential and natural intelligible part in which it makes them intelligible, we now write this Book of Light which enables the intellect to become fluent in the science of the General Art, and this book proceeds according to the mode of the General Art (Ars Magna, or Ars Generalis Ultima) whose Principles and Rules it adopts. Now this Book is like a knot tied in a rope to prompt the memory to recollect things."

Raymond Lull (1247), The Book of Light/Liber de Lumiere
http://ladyofroses.org/Lumine/00pr.htm