Kelim, Chapter Twenty-Nine, Mishnah Two
1) Three woolen pillow-covers, six linen ones, three sheets, twelve handkerchiefs, two pant-sleeves, one shirt, one cloak, or one winter-cloak, can be regarded as connected in respect of both uncleanness and sprinkling.
2) If they exceed this number they are regarded as connected in respect of uncleanness but not in respect of sprinkling.
a) Rabbi Yose says: not even in respect of uncleanness.
Section one: If one sews or weaves together a combination of these numbers of items, they are considered connected in terms of both uncleanness and sprinkling. What this means is that if one becomes impure, all are impure and if one is sprinkled with the waters of purifications (red heifer waters) all are clean.
Note that the number of pieces that can be sewn or woven together depends on the size of the cloth. Small pieces such as handkerchiefs can have large numbers but larger garments such as a cloak cannot be considered as connected to other cloaks. Once something is that big, attaching it to another large piece would be cumbersome and probably was not done. It seems to me that the smaller pieces may have been sewn together by merchants carrying them to market.
Section two: If there are more than this number sewn together the law is stringent. This means that they are regarded as connected for matters of uncleanness, so if one is unclean all are unclean. But when it comes to purification, they are not considered connected, and all must be sprinkled upon for them to be pure.
Rabbi Yose says that the law is consistent. Just as they are not considered connected with regard to the laws of sprinkling, so too with regard to the laws of uncleanness they are not considered connected.