Does anyone know of a good video about the Buffon needle problem that includes the calculus-free proof via linearity of expectation? I just spent a few minutes on YouTube and found a couple of videos that went that route, but they didn’t do it in a clear way. (Jordan Ellenberg gives this proof in his book “How Not to Be Wrong”, but the laypeople I’ve spoken to about this part of his book found it hard to follow, so I think a lengthier explanation is required, especially one that includes visuals.) You would think that with all the hoopla about Pi Day, someone would have already made such a video! Jim Propp (PS: Hmm, “hoop”-la about Pi Day?)