Bava Batra 60A

ולסתום ⁠– לאלתר הוי חזקה, שאין אדם עשוי שסותמים אורו בפניו ושותק.

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.

לקח בית בחצר אחרת ⁠– לא יפתחנו לחצר השותפין. מאי טעמא? מפני שמרבה עליהם את הדרך.

§ The Mishnah teaches that if one purchased a house in another, adjacent courtyard, he may not open the house into a courtyard belonging to partners. The Talmud 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.

אימא סיפא: אלא אם רצה ⁠– בונה את החדר לפנים מביתו, ובונה עלייה על גבי ביתו. והלא מרבה עליו את הדרך! אמר רב הונא: מאי חדר? שחלקו בשנים, ומאי עלייה? אפתאי.

The Talmud questions this. But say the last clause of the Mishnah: 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 Mishnah 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 Mishnah is referring? It is an internal story created by dividing an existing space into two stories.