And to seal, i.e., if one sealed another’s window in his presence, there is an acquired privilege established immediately to keep the window sealed, as it is not common behavior for a person to have his source of light sealed in his presence and remain silent. The fact that he did not immediately protest indicates that the one who sealed the window had the legal right to do so unilaterally, or that the owner of the window agreed.

§ The mishna teaches that if one purchased a house in another, adjacent courtyard, he may not open the house into a courtyard belonging to partners. The Gemara explains: What is the reason for this? Because by adding residents to the courtyard it increases their traffic, and the residents of the courtyard do not wish to be disturbed by additional people passing through.

The Gemara questions this. But say the last clause of the mishna: Rather, if he desired to build a loft, he may build a room within his house, or he may build a loft above his house, and have it open into his house, not directly into the courtyard. But if he does so, isn’t there still a concern that it increases the traffic? Rav Huna said as an explanation: What does the mishna mean when it says that he may build a room? It means that he may divide an existing room in two. And what is the loft to which the mishna is referring? It is an internal story created by dividing an existing space into two stories.

MISHNA: A person may not open an entrance opposite another entrance or a window opposite another window toward a courtyard belonging to partners, so as to ensure that the residents will enjoy a measure of privacy. If there was a small entrance he may not enlarge it. If there was one entrance he may not fashion it into two. But one may open an entrance opposite another entrance or a window opposite another window toward the public domain. Similarly, if there was a small entrance he may enlarge it, and if there was one entrance he may fashion it into two.

GEMARA: The Gemara asks: From where are these matters, i.e., that one may not open an en-trance opposite another entrance, or a window opposite another window, derived? Rabbi Yoḥanan says that the verse states: “And Balaam lifted up his eyes, and he saw Israel dwelling tribe by tribe; and the spirit of God came upon him” (Numbers 24:2). The Gemara explains: What was it that Balaam saw that so inspired him? He saw that the entrances of their tents were not aligned with each other, ensuring that each family enjoyed a measure of privacy. And he said: If this is the case, these people are worthy of having the Divine Presence rest on them.

The mishna teaches that if there was a small entrance he may not enlarge it. Rami bar Ḥama thought to say this means that if the entrance was the width of four cubits, one may not fashion it to the width of eight cubits, as he would then be allowed to take eight corresponding cubits in the courtyard. The halakha is that one is entitled to utilize the area of the courtyard up to a depth of four cubits along the width of the opening. But if the entrance was the width of two cubits and one wishes to fashion it to the width of four cubits, one may well do so, as in any event he already had the right to use an area of four cubits by four cubits in front of the entrance. Rava said to him: This is not so, as his neighbor can say to him: I can conceal myself from you with there being a small entrance, but I cannot conceal myself from you with there being a large entrance.

The mishna teaches that if there was one entrance he may not fashion it into two. In this case as well, Rami bar Ḥama thought to say that this means if the entrance was the width of four cubits he may not make it into two openings, each the width of two cubits, as he would then be allowed to take eight corresponding cubits in the courtyard, four for each entrance. But if it was the width of eight cubits and he wishes to make it into two openings, each the width of four cubits, he may well do so, as in any event he already had the right to use an area of eight cubits by four cubits in front of his entrance. Rava said to him: This is not so, as his neighbor can say to him: I can conceal myself from you with there being one entrance, but I cannot conceal myself from you with there being two entrances.

The mishna teaches: But one may open an entrance opposite another entrance or a window opposite another window toward the public domain. Why is this so? Because he can say to the one who wishes to protest: Ultimately, you must conceal yourself from the people of the public domain. Since you cannot stop them from passing by and therefore cannot engage in behavior that requires privacy with your entrance open, it is of no consequence to you if I open an entrance as well.

MISHNA: One may not form an empty space be-neath the public domain by digging pits, ditches, or caves. Rabbi Eliezer deems it permitted for one to do so, provided that he places a covering strong enough that a wagon laden with stones would be able to tread on it without breaking it, therefore ensuring that the empty space will not cause any damage to those in the public domain. One may not extend projections or balconies [ugzuztraot] into the public domain. Rather, if he desired to build one he may draw back into his property by moving his wall, and extend the projection to the end of his property line. If one purchased a courtyard in which there are projections and balconies extending into the public domain, this courtyard retains its presumptive status, i.e., the owner has the acquired privilege of their use, and the court does not demand their removal.

GEMARA: The Gemara asks: Rabbi Eliezer’s opinion that if the covering of the space is strong enough to support a wagon laden with stones then it is permitted to dig out the empty space, is eminently reasonable; but what do the Rabbis hold? The Gemara answers: There are times when the cover erodes over time, and he is not aware, thereby potentially causing damage to those in the public domain.

The mishna teaches that one may not extend projections or balconies into the public domain. The Gemara relates: Rabbi Ami had a projection that protruded into an alleyway, and a certain man also had a projection that protruded into the public domain, and the general public was preventing the man from leaving it there, as it interfered with traffic. He came before Rabbi Ami, who said to him: Go sever your projection.

The man said to him: But the Master also has a similar projection. Rabbi Ami said to him: It is different, as mine protrudes into an alleyway, where a limited number of people live, and the residents of the alleyway waive their right to protest to me. Yours protrudes into the public domain, which does not belong to any specific individuals. Who can waive their right to protest to you?

The Gemara relates: Rabbi Yannai had a tree that was leaning into the public domain. There was a certain man who also had a tree that was leaning into the public domain, and the general public was preventing him from leaving it there, insisting he cut it down, as required by the mishna (27b). He came before Rabbi Yannai, who said to him: