Can you explain the 'tortoise-vision' (Kurma-drishti) analogy that Baba used and what it teaches about devotion?

In Chapter 19, Sai Baba uses the analogy of a mother tortoise to illustrate the nature of devotion and the Guru's grace. He describes how the mother tortoise can be on one bank of a river while her young are on the other. She nourishes them not with milk or warmth, but solely with her gaze, which he calls 'tortoise-vision' or Kurma-drishti. The young ones simply meditate on their mother, and her loving gaze is all the nourishment they need. This powerful metaphor teaches that a devotee's focused meditation on the Guru is sufficient for their spiritual nourishment and progress, just as the mother tortoise's sight sustains her offspring without any physical contact.