A mat in which one placed reed [stalks] along its length is tahor. But the Sages say: Only if [the stalks] are laid similar to the shape of a ki. [If] he placed [the reed stalks] along [the mat’s] width but there are not four handbreadths between one reed and the next, it is tahor. [If] it split in its width, R’ Yehudah rules it tahor. And similarly, if one unties the end knots, it is tahor. [If] it split in its length and three end knots remained of six handbreadths, it is tamei. From when does a mat become susceptible to tumah? From when it is trimmed, and this [represents] the completion of its manufacture.