ציטירנדיקער פּירוש אויף דניאל 6:10

Even ten vessels one on another. As it is written, “Whoever sits on the vessel that was sat upon by a zov.” This makes a comparison between the sitting of the pure person and the sitting of the zov: Just as the sitting of the zov causes impurity to the vessels even though he does not sit on the vessel, such as the case of the “placed” stone (see later), so too is the sitting of the pure person who acquires impurity from the vessel which contracted impurity from the zov, even if he does not touch it. A “placed” stone is a stone placed on pegs with vessels underneath it, as it is written (Daniel 6:18): “And a stone was brought and placed on the mouth of the pit.” If a menstruant woman or a zov sit on it, even though their weight is not felt on the vessels, the vessels are impure, as it is written (v. 10): “Anything which is beneath him.” Rashi (Shabbos 82b).