On a snowy wintry day, it almost looks like everything is made out of snow. Sometimes the snow is pulled into the shape of a mailbox, sometimes into the shape of a person. The monk's question, "Does a dog have Buddha nature?", comes from a place of difference. Joshu's answer, "Mu" comes from a place of undifferentiated oneness. A place where differences don't make a difference. Like the snow, in practicing Mu, all differences are smoothed out into this one sound, this one substance.