Sukkah 20a and Sukkah 20b, finishing the first chapter with a discussion of the kinds of mats we assume are for sleeping on (and therefore not valid as sechach), which mats are susceptible both to tumat met and midras, the kind of ritual impurity conveyed by a zav or zavah sitting or lying on it, how a ridge or railing around a mat converts it into a usable item and therefore is invalid as sechach. Then, beginning the second chapter, sleeping under a bed and how that affects one’s sukkah observance.
