(Mishnah): A reed fence - if there isn't a space between one reed and the next of 3 Tefachim, which is enough room for a kid to enter, it's considered a partition. If a fence was breached, up until 10 Amos wide, it's considered like a doorway; more than 10 Amos is considered a breach.

If it had many breaches, if the solid is more than the airspace, it is permitted; if the airspace is more than the solid, what is adjacent to that breach is prohibited.

(Gemara): If he made posts opposite the breaches (that are between the rows of vines) and the posts are four Tefachim wide, so that the solid is now more than the breach, that which is opposite the solid is permitted; opposite the breach is prohibited.

If he made posts opposite the vines that weren't four Tefachim wide, so that the breach was more than the solid, it is obvious that opposite the solid is permitted and opposite the breach is prohibited.

(R. Shimon ben Lakish citing R. Yehuda ben Chanina): If one inserted four canes into the four corners of a vineyard and tied reeds between them on the top, we view the area inside as a separate field for the laws of Kilayim. (The canes with the reeds above them serve as a doorway and this is effective even if the canes are more than ten Amos apart - this arrangement is referred to as Pe'ah. See earlier Menachos 48(a))

(R. Yochanan): Partitions for Kilayim follow the laws of partitions on Shabbos (that the poles must not be more than ten Amos apart).

(R. Yochanan): There was a story of R. Yehoshua ben Karchah who went to visit R. Yochanan ben Nuri in Negninar and R. Yochanan showed him a field called Beis Chavertah. There were breaches in the fence wider than ten Amos and he had taken wood and poles and put them in between in order to narrow the breaches to less than ten, (thereby allowing him to plant other seeds behind it). R. Yochanan ben Nuri said that this would be a valid partition for Shabbos. (This story disagrees with the ruling of R. Shimon ben Lakish.)

Answer (R. Zeira): R. Shimon ben Lakish agrees that in the laws of Shabbos, it does not help if the poles are more than ten Amos apart.

Support (R. Chagai)(Mishnah): (For Shabbos) one may enclose an area with three ropes one above the other (if they are within three Tefachim of each other).

If you would say that it helps even if the poles are more than ten Amos apart, using just one rope (on top) would suffice as it would create a doorway?!

Question (R. Yona quoting R. Yashiyah): Where does one string up the reeds - above the poles or between the poles (near the top)?

If you say that it is above the poles then certainly it would be effective if put between them; if you say that it is between the poles, above them would not work.

If you say that it is above the poles, R. Chagai has no proof from the Mishnah about Shabbos.

Rebuttal: Either way, R. Chagai is correct. R. Chagai's Mishnah discusses three ropes, one above, one below and one in the middle. If you say positioning the reed between the poles is valid, why would the Mishnah require the top and bottom ropes? If you say it must be on top, why would the Mishnah require the middle and bottom ropes?

) Answer (Rabbanan of Kisarin quoting R. Yirmiyah): Pe'ah is effective for Kilayim when the poles are filed to come to a point at the top. Therefore, the reed can only be tied on the side but not on top, so three ropes are required in order to create a partition using the law of Lavud. (Note: This entry and the one that follows are according to the explanation of Rav Chaim Kanievski.)

(R. Zeira/ R. Avudama of Haifa quoting R. Shimon ben Lakish): Pe'ah is valid even if the poles and reed are one hundred Amos tall.

(R. Yudan): This is only true for a partition for Kilayim, but for a partition for Shabbos, the Pe'ah (poles+reed) should not be higher than the maximum permitted height of a beam across the entrance to a Mavoi (i.e. 20 Amos).

(R. Yosi): In this law, Kilayim and Shabbos are the same (as even for Shabbos, Pe'ah will be effective as high as one hundred Amos).

Question: According to R. Yosi, on Shabbos, why is Pe'ah different to a beam across a Mavoi (that can only be as high as 20 Amos)?

Answer: Pe'ah is only effective when it surrounds on all four sides. A beam is effective on just one side.

This follows the opinion of Rav Zeira quoting Rav Hamnuna who said that Pe'ah is only effective when it is surrounds on all four sides.