Because addresses the house's "stones" in the plural, Rabbi Akiva ruled that a sign of house plague was no cause of uncleanness unless it appeared in at least the size of two split beans on two stones, and not on only one stone. And because addresses the house's "walls" in the plural, Rabbi Eliezer son of Rabbi Simeon said that a sign of house plague was no cause of uncleanness unless it appeared in the size of two split beans, on two stones, on two walls in a corner, its length being that of two split beans and its breadth that of one split bean.