What do the three and a half turns of Kundalini symbolize?

Answer from the V.M. Samael Aun Weor and the magazine.

"Kundalini Yoga also brilliantly teaches that Bhujanjini, or serpent power, is coiled three and a half times within the root chakra. These three turns represent the three gunas of Prakriti: Sattva, Raya, and Tamas.

It is an axiom of esoteric wisdom that the remaining half of the tail represents Vikriti, the modification of Prakriti, the eternal feminine."

Samael Aun Weor. Excerpt from the book: My Return to Tibet. The Wisdom of Being Magazine. 108. The Three and a Half Turns of Kundalini.