Math can get pretty loopy, at least when we try to explain it. But according to author Alex Bellos, the most straightforward mathematical concept might be the loopiest. Then producer Mark Philips introduces us to William Basinski, a composer who loops analog tape to create a unique sort of music. One day, Basinski dug up some of his old tapes, stuck them into his player, and heard a melody in the throes of death.

Life and death are a very long loop of their own, as producer Lynn Levy discovered in talking with oceanographer Craig Smith. His career began with a simple question: what happens to a whale when it dies and sinks to the sea floor? Turns out nobody was quite sure. Craig describes the curious interplay between death and life at the bottom of the ocean.