Many chapters of Mishnah are also framed by inclusio. In the opening mishnah of Taanit, Rabbi Joshua notes that rain on the festival of Sukkot is "not a sign of blessing", and the closing mishnah of the chapter notes that rainfall after the month of Nisan is "a sign of curse". This characterization of rainfall as God's way of communicating His blessings and curses is a central theme of the chapter. Sometimes the inclusio is based on a wordplay. Ohalot Chapter 7 opens with a discussion of corpse impurity in a ""nefesh atuma"" ("solid monument")and closes with the statement that a baby whose head has emerged from the womb may not be killed to save the mother because ""ayn dochin nefesh mipnei nefesh"" ("one soul may not be set aside in favor of another"). The use of the word "nefesh" at the beginning and the end of the chapter in opposite meanings, symbolizing respectively death and life, emphasize the interconnection between the mysteries of birth and of death.