What is the meaning of the 'logic of the branch and the moon' as it relates to Sai Baba's big toe?

The 'logic of the branch and the moon' is an analogy used in Chapter 22 to explain how Baba provided an accessible point of focus for devotion. Just as one might use a tree branch to point out the faint crescent moon in the sky, Baba offered his own form to fulfill his devotees' longing for a spiritual vision. When devotees yearned for a glimpse of the divine, Baba would sit with his right foot over his left knee. He would then indicate that the shining nail on his big toe was like the crescent moon. By focusing their gaze there, devotees could satisfy their spiritual curiosity and find an easy means of devotion, as Mother Sai showed them an easy way to Him.