Pisces. Zhuang Zhou and Hui Tzu were once walking along a creek. They climbed onto a bridge to observe the fish swimming in the creek's clear waters below. "Look how happy the fish are!" Zhuang Zhou exclaimed to his friend. "You are not a fish. So how do you know whether the fish are happy or not!" retorted Hui Tzu. "You are not me. So how can you know if I know what makes fish happy?" With that, Zhuang Zhou ended the argument, and the two friends passed over to the other side of the creek.