[The crossbeam] of an alley [whose entrance] is more than twenty cubits high should be lowered. Rabbi Judah says: this is unnecessary. And [any entrance] that is wider than ten cubits should be reduced [in width]. But if it has the shape of a doorway there is no need to reduce it even though it is wider than ten cubits.

The validation of an alley: Bet Shammai says: a side-post and a crossbeam. And Bet Hillel says: either a side-post or a crossbeam. R. Eliezer says: two side-posts. In the name of Rabbi Ishmael one student stated in front of Rabbi Akiva: Bet Shammai and Bet Hillel did not disagree concerning an alley that was less than four cubits [in width], that it [may be validated] by either a side-post or a crossbeam. About what did they disagree? In the case of one that was wider than four, and narrower than ten cubits: Bet Shammai says: both a side-post and a crossbeam [are required] and Bet Hillel says: either a side-post or a crossbeam. Rabbi Akiva said they disagree about both cases.

The cross-beam of which they spoke must be wide enough to hold a small brick (ariah), a small brick which is half of a regular brick, the size of three handbreadths. It is enough for the cross-beam to be one handbreadth wide in order to hold the width of a small brick.

Wide enough to hold a half-brick but also strong enough to support such a half-brick. Rabbi Judah says: wide enough, even though it is not strong enough.

If [the cross-beam] was made of straw or reeds, we look at it as if it was of metal. [If it was] curved we look at it as if it were straight. [If it was] round we look at it as if it were square. Whatever has a circumference of three handbreadths has a diameter of one handbreadth.

The side-posts of which they spoke [must be no less than] ten hand-breadths in height, but their width and thickness may be of any size whatsoever. Rabbi Yose says: their width [must be no less than] three handbreadths.

One may make the side-posts out of anything, even something that is alive. But Rabbi Yose prohibits this. It also causes defilement as the covering of a tomb, But Rabbi Meir makes pure. One may write on them gittin, But Rabbi Yose the Galilean declares it unfit.

If a caravan camped in a valley and it was surrounded by the instruments used for the cattle it is permissible to move objects within it, provided [the instruments] form a fence ten handbreadths high and the gaps do not exceed the built-up parts. Any gap which is approximately ten cubits it is permitted [to carry within], because it is like an entrance. If it is greater, it is forbidden [to carry within].

They may surround [the caravan] by three ropes, this one above this one, and this one above this one, provided that [the space] between the one rope and the other is less than three handbreadths. The size of the ropes [must be such] that their [total] thickness is more than a handbreadth, so that the total height is ten handbreadths.

They may also surround [the camp] with reeds, provided there is no [gap of] three handbreadths between one reed and the next. [The rabbis] spoke only of a caravan, the words of Rabbi Judah. But the sages say that they only spoke of a caravan because it is a usual occurrence. Any partition that is not [made up of] both vertical and horizontal [pieces] is not a valid partition, the words of Rabbi Yose bar Judah. But the sages say: one of the two [is sufficient]. They exempted four obligations [to soldiers] in an encampment: They may bring wood from anywhere; they are exempt from the washing of the hands, and from [separating tithes from] doubtfully tithed produce (demai) and from the setting up an eruv.