The Invisible 13 Pointed Star: This is perhaps the most important part of the labyrinth. The points of the star connect to the outer lunations from the center. The lines of the star determines where the petals at the center will be placed. It is most difficult to reproduce an 11-circuit labyrinth without knowledge of this 13 pointed star. The number 13 comes from the Pythagorean system of geometry that was used to lay out the labyrinth at the Chartres Cathedral. 13 is a prime number (meaning that it cannot be divided or reduced) so it is seen in Greek forms as an expression of the prime creator. In some versions of numerology, 13 is the number of Christ (12 plus 1). It is also symbolic of the 13 full moons in a year. A person who walks the labyrinth turns toward the center 13 times before the walk is complete.

Dr. Lauren Artress says in her book Walking A Sacred Path: Rediscovering The Labyrinth As A Spiritual Tool (1995), ...I believe the invisible star empowers the labyrinth in some inexplicable way. It establishes the pattern for the flow of energy that allows the seeker to have solid and integrative experiences. I have walked classical 11-circuit labyrinths that were drawn into linear fashion, without the guidance of the star, and they were not as powerful or centered as they should have been....

The 13 pointed star circuit, circular design labyrinth, seen at the charters cathedral comes from the Pythagorean system. The ...Walking a Sacred Path... book by Dr. Lauren Artress gives reference to a meditate maze: a spiritual walk with a spiral circle leading to the center.