The letter Shin signifies the trinity of the first three Sephiroth. The central circle slightly above the other two is the first Sephira—Kether, the White Head, the Crown. The other two circles represent Chochmah, the Father, and Binah, the Mother. From the union of the Divine Father and the Divine Mother are produced the worlds and the generations of living things. The three flame-like points of the letter have long been used to conceal this Creative Triad of the Kabbalists. MPH