Can you describe Sai Baba's unusual sleeping plank and explain what made it seem miraculous?

Chapter 10 provides a detailed description of Sai Baba's extraordinary sleeping arrangement. He would rest on a simple wooden plank, merely four cubits long and one span (about nine inches) wide, which was suspended from the rafters like a swing using old rags. The miracle, as highlighted in Chapter 10, was twofold: firstly, how such a flimsy setup could support his weight, and secondly, that his movements—when he climbed up or descended—were completely imperceptible. No one ever witnessed him getting onto or off the plank, suggesting this was a display of his great Siddhis (powers), not a normal physical act.