זוהר שמות — דף קפ ע”א

The 'Sod ha-Yod' unveils the mystery of the letter Yod: the first point of the letter Yod stands upon nine pillars that support it, standing toward the four sides of the world. Likewise the end of thought — the final point — stands toward the four sides of the world. The Yod in square form stands at the measure of nine points, three on each side. These nine are eight in the secret of the square Mem letter. Twelve superior points descend toward the six extremities, and when these twelve are engraved in the six extremities, they form seventy-two Names — the secret of the Holy Name.