Sukkah 7a and Sukkah 7b, where to put the third wall of the sukkah, how sukkah walls can count for Shabbat purposes on the Shabbat of Sukkot, and vice verse, how Shabbat walls can count for a sukkah on that Shabbat, and then the tannaim who held a sukkah had to be a dirat keva, a structure with some permanence.
