I finished my second visit recently. I was shadowing a program faculty in inpatient round. I performed well. At the end of the day, when I was leaving, in the elevator, I met the Chair of the program, whom I only saw on the program website. I quickly gathered myself and introdued myself to him. I expressed my interest in the program and I can tell that he liked what I said. We had a nice chat while walking together outside the building. Should I write thank you letters for my second visit? Which people should i write the letter to, the faculty whom I rounded with, the residents whom I rounded with, the program director (whom I did not see on my second visit), or the Chaiman of department whom I met in elevator by sheer luck and chatted with?