What is the 'tortoise-vision' or 'Kurma-drishti' that Baba mentions, and how does it relate to spiritual practice?

Sai Baba uses the powerful analogy of 'tortoise-vision' or 'Kurma-drishti' in Chapter 19 to illustrate the profound power of focused attention and the Guru's grace. He explains that a mother tortoise on one river bank can nourish her young on the other side with her gaze alone, without providing physical milk or warmth. The young ones simply need to meditate on the mother. This metaphor shows how a disciple's constant meditation on their Guru provides all necessary spiritual nourishment. The gaze of the Guru, like the tortoise's, is a source of grace and sustenance for the devotee who remains focused.