[If] a patch was sewn onto a basket, it contaminates one and invalidates one. [If] one [then] separated it from the basket, the basket contaminates one and invalidates one, but the patch becomes tahor. [If] it was sewn onto a cloth, it contaminates two and invalidates one. [If] he [then] separated it from the cloth, the cloth contaminates one and invalidates one, but the patch contaminates two and invalidates one. The same applies if one sewed [a patch] onto sack or onto leather; [these are] the words of R’ Meir. R’ Shimon rules that it is tahor. R’ Yose says: [If he sewed the patch] onto leather, it is tahor; onto sack, it is tamei, since it is woven.