(Mishnah): One who sows two vines opposite two and one coming out like a tail : : .

If there are two opposite two with one in between : . : or two opposite two with one in the middle : - : it's not a vineyard until has two opposite two with a tail (as above).

(Gemara) (R. Chiya bar Bar citing R. Chiya bar Yosef): (The source for the minimum number of vines that make a vineyard is) the pasuk (that) states (Bamidbar 34:2), "the Land of Canaan according to its borders'' - borders that were established by the Canaanites (who would plant vineyards in this arrangement).

Objection (R. Imi): Do we learn from the behaviour of the Canaanites?! (Rather, it is a Halacha L'Moshe MiSinai.)

(Shmuel): In order to measure the required 4 Amah distance from the vineyard, one must view it as if there is a string extending diagonally from the second vine in the two-vine row, to the third vine in the three-vine row (i.e. to the tail) and then measure 4 Amos away from that string.

(R. Yosi bar Zemina citing R. Yochanan): No - rather, one views it as if there is a third vine planted in the row next to the tail and one then measures 4 Amos from there.

Question (R. Yona): If there were two 'vineyards' back to back, in an arrangement of 4 and 2 ( .::. ), do we view it as two rows of four (as if an additional vine was planted on each side of the 2 vine row (since we don't know which side is the tail)?

Question #2: If one planted 3 opposite 3, with a tail coming from out of the middle (meaning below the middle pair in this picture : : : , so that it could be considered the tail of either side), do we view it as if there is another vine planted on each side of that protrusion (since we don't know for which side the protruding one serves as the tail)?

Question: Didn't you say that a large vineyard doesn't have tail? (See earlier Menachos 57(i))

Rebuttal: That's in the case of a large vineyard (and here, it can't be considered large); but the question is - could one gave a tail to a small vineyard and make it large?

(Mishnah): One who plants one row (of two vines) within his property and one row (of three vines) in his friend's property and there is a private or public path or a fence lower than 10 Tefachim passing between them, they combine to create a vineyard.

If the fence is taller than 10 Tefachim, they don't combine.

(R. Yehuda): If he entwined them above (the fence) they combine.

(Gemara) Question (R. Acha): Doesn't this disagree with R. Shimon, who said that a person cannot prohibit that which is not his...?

Answer: There, it isn't his; here, he partially owns it.

R. Mana explained differently - R. Shmuel said in the name of R. Zeira, that R. Shimon follows his reasoning - just as he said that a person cannot prohibit that which isn't his; so too a person cannot surround that which is not his (thereby preventing the other person from planting).

There (surrounding) - a person cannot prohibit that which isn't his; but here (vineyard), both his and his neighbor's combine to prohibit.