Keilim, Chapter 16, Mishnah 3. This chapter tracks the point in a craftsman's work at which an object stops being raw material and becomes a finished utensil, for only a completed kli can receive tumah. Our mishnah applies that principle to a series of woven and coiled containers, each one reaching completion at a slightly different stage of the work.
The mishnah begins: "Hakinnonin haketanim vehakelatot". The kinnonin haketanim are small sifters fashioned from palm leaves, typically used for sifting beans. The kelatot are small baskets woven from reeds or straw, the sort of container women used for keeping small items close at hand.
When do these become susceptible to tumah? "Misheyachsom viychannev": once the craftsman has finished off their rims and then trimmed them, snipping away the twig ends that protrude on the inside and on the outside. Until then the piece is still rough work; once those two steps are done, the container is fit for use, and a utensil fit for use can contract tumah.
Up to this point the mishnah has dealt with containers produced by weaving strands together. It now turns to containers made by a different technique: coiling, in which a long cord or rope of material is wound around and around in a series of loops to build up the walls of the vessel.
"Hakinnonim hagedolim vehasugim hagedolim": the large sifters, and the large bins in which merchants store grain that they sell in bulk. Regarding these the mishnah rules "misheya'aseh shenei durin larohav shelahem": after the base has been made, they become susceptible to tumah once the craftsman has wound two coils around the perimeter, forming the beginning of a wall.
The mishnah continues with "Hanaffah vehakevarah vechaf shel moznayim". A naffah is the woven straining surface of a sifting implement, encircled by a border of its own; a kevarah is the sifter through which grain is passed so that the unwanted matter is separated off, and it likewise has a border running around it. Grouped with them is the dish of a scale used for weighing, which was also produced out of plaited reeds. In all three cases the halachah is "misheya'aseh dur echad larohav shelahen": they enter the category of utensils that can contract tumah as soon as one loop has been coiled around the circumference. In objects shaped like these, a border consisting of one round of plaiting already renders the item serviceable, and once it is serviceable it is open to tumah.
A further method of construction now comes up for discussion. "Hakuppah" is a basket assembled out of individual hoops fastened one onto the next. Its halachah is "misheya'aseh shtei sefirot larohav shelah": tumah can take hold in it from the point at which the craftsman has fixed two such hoops onto the bottom piece, thereby raising up a side.
The mishnah closes with "veha'arak, misheya'aseh bo sefirah achat". An arak is a low, oblong reed container. Because it is fashioned on purpose to be less deep than the kuppah of the previous clause, one hoop fitted onto its bottom already leaves it fit for use, and from that stage onward it is subject to tumah.
The thread running through the entire mishnah is one measure applied case by case: a vessel becomes a vessel when it can do the job it was designed for. A deep grain bin needs two coils before it holds anything; a flat sifter or scale pan needs only one; a shallow reed basket needs a single ring where a deeper basket needs two. The craftsman's own intended shape determines the moment his work becomes a kli.