Could you describe the unusual plank Sai Baba used for sleeping as mentioned in the text?

Certainly. Chapter 10 provides a detailed description of Sai Baba's unique sleeping arrangement. He would rest on a wooden plank that was four cubits long but only one span, or about nine inches, wide. This narrow plank was not on the floor but was hung from the rafters like a swing, suspended at both ends by old rags. The chapter notes that despite this precarious setup, Baba would sleep soundly on the plank, often with lamps burning at his head and feet, showcasing his extraordinary nature.