The adjustment of an alley — Beis Shammai say: A pole and a crossbeam. But Beis Hillel say: A pole or a crossbeam. R’ Eliezer says: Two poles. A disciple — in the presence of R’ Akiva — stated in the name of R’ Yishmael: Beis Shammai and Beis Hillel did not differ concerning an alley which is narrower than four cubits that it may be [adjusted] with a pole or a crossbeam. Concerning which did they differ? Concerning one which is wider than four cubits and up to ten cubits. Beis Shammai say: A pole and a crossbeam. But Beis Hillel say: A pole or a crossbeam. Said R’ Akiva: They differed in both cases.

The crossbeam of which they spoke — it is wide [enough] to hold an ariach; an ariach is half a brick measuring three fists. It is sufficient for the crossbeam to be one fist wide to hold an ariach lengthwise.

Wide [enough] to hold an ariach and strong [enough] to hold an ariach. R’ Yehudah says: Wide, even if it is not strong.

If it was [made] of straw or of reeds, we view it as if it were [made] of metal; bent, we view it as if it were straight; rounded, we view it as if it were squared. Anything which has a circumference of three fists has a diameter of one fist.