One who sleeps under the bed in the succah has not fulfilled his obligation [to sleep in a succah].  R’ Yehudah said: We regularly slept under the bed in the presence of the Elders and they said nothing to us.  R’ Shimon said: There is a case of Tavi, Rabban Gamliel’s slave, who used to sleep under the bed. Rabban Gamliel said to the Elders, “Have you observed my slave Tavi? He is a scholar and knows that [gentile] slaves are exempt from [the obligation of] succah —- that is why he sleeps under the bed.” And incidentally we deduced that one who sleeps under the bed does not fulfill his obligation [to sleep in a succah].

If one supports his succah on the legs of a bed, it is valid. R’ Yehudah says: If it cannot stand by itself it is invalid.  A disarranged succah, or one whose shade[d area] is greater than its sun[lit area], is valid. [If the succah] is thickly covered like a house, even though the stars cannot be seen from inside it, it is valid.

If one makes his succah on top of a wagon or on the deck of a ship it is valid, and we may go up into it on the festival. [If he makes a succah] in the top of a tree or on the back of a camel it is valid, but we may not go up into it on the festival.  If two [walls are] in a tree and one is man-made, or two [are] man-made and one [is] in a tree, it is valid, but we may not go up into it on the festival. If three [walls are] man-made and one [is] in a tree, it is valid, and we may go up into it on the festival.  This is the general rule: Wherever the tree can be removed and [the succah] can stand by itself, it is valid, and we may go up into it on the festival.

If one makes his succah between the trees, and the trees serve as its walls, it is valid.  Those who are engaged in the performance of a mitzvah are exempt from the [mitzvah of] succah. Ill people and their attendants are exempt from the [mitzvah of] succah.  We may eat and drink casually outside the succah.