What's the story behind the wooden plank Sai Baba slept on?

The story of the plank began because the Masjid where Maharaj slept was in a dilapidated state. According to chapter 0, a devotee named Nanasaheb Dengle brought a thick wooden plank for Maharaj so he would not have to sleep on the bare, dusty ground. Instead of using it as intended, Maharaj hung the plank from the rafters of the Masjid using old rags and began sleeping on it. This unusual sleeping arrangement became a point of great curiosity, with many people gathering to witness it, though no one ever saw him ascend or descend from the plank.