Bava Batra 101B

קבורת חמורים היא זו!

This is like a burial of donkeys and is disrespectful.

לרבי יוחנן, דעביד להו בקרן זוית.

The Talmud answers: According to the opinion of R' Yoḥanan, each of these two niches is formed in a different corner of the chamber, aligned diagonally away from the chamber’s cavity.

והא נגעי כוכין להדדי!

The Talmud challenges: But if so, won’t the niches located around the corners touch one another? According to R' Yoḥanan’s suggestion, there are, in fact, 3 niches located at each of the two back corners. One is recessed into the wall of the length of the chamber, at right angles to it, another is recessed into the back wall of the chamber, also at right angles to it, and a third that extends diagonally away from the chamber. The ends of these 3 niches will overlap, causing there to be too little space in them to fulfill the minimum required measurement.

אמר רב אשי: במעמיק. דאי לא תימא הכי, ארבע מערות לרבי שמעון ⁠– היכי עביד להו? הא קא נגעי כוכין להדדי! אלא במעמיק; הכא נמי במעמיק.

Rav Ashi said: It is possible to do this where, when constructing the niches that extend diagonally away from the chamber, one deepens them, i.e., forms them lower down in the wall than the other niches adjacent to them. As, if you do not say that this is a solution, then how could the 4 chambers depicted by R' Shimon be constructed? Won’t the niches touch one another? The niches of one chamber will overlap those of the chamber adjacent to it. Rather, it is possible to arrange the niches only where, when constructing the niches of two chambers at opposite ends of the courtyard, one deepens them, i.e., forms them lower down in the wall than the niches of the other two chambers that are adjacent to them. Here too, it is a case in which one deepens them.