Can you tell me about the instances where Lord Vitthal appeared to devotees in Shirdi?

Chapter 4 details a couple of significant instances where Lord Vitthal manifested to devotees in Shirdi. First, when Baba instructed Das Ganu to organize a Name-week (Saptah), Das Ganu expressed a desire for Vitthal to appear. Baba promised that Vitthal's form would indeed appear, provided the devotee was full of faith. The text confirms that at the end of the Saptah, Das Ganu was blessed with the sight of Vitthal in Shirdi. In another case, Kakasaheb Dixit had a vision of Vitthal during his morning meditation. When he later went for Baba's darshan, Baba confirmed the vision by asking, "Vitthal Patil had come, right?" and advised him to "nail him down and make him steady," meaning to hold on to the spiritual experience. The vision was further validated when a traveling seller arrived with pictures of Vitthal, one of which was an exact replica of what Kakasaheb had seen in his meditation.