Sukkah 15: Structural Incongruities

A daf with 2 mishnayot. The first has 3 different disputes in the span of the one mishnah, which focuses on wooden boards that can be used for schach, depending on the finished product. How wide can the board be? What if you remove a board? And most importantly, perhaps, how do we apply other basic sukkah concepts to this new scenario of sukkah. Also, the second mishnah - metal skewers or bed rods for schach.... Plus one who digs a sukkah out of a pile of grain... Which poses a structural question about the mishnah. The next daf may have an easement to that structural difficulty. Also, the Gemara delves into the question of the poles being placed at a distance from each other equal to the width of the pole.