This line alludes to a story of Xi Kang/Hsi K'ang (223-62) and Lü An (d. 262) recorded in the Shishuo Xinyu, or the New Account of Tales of the World. They often traveled long distances to see each other. Once Lü went to visit Xi but the latter was not at home. His elder brother Xi Xi went out to greet Lü, who refused to enter the house. Instead he wrote the character "phoenix" (feng) on the door and left. Xi Xi was delighted because he thought Lü meant to compliment him by comparing him to the lofty bird. What Lü had in mind, however, was to criticize him, by saying that he was nothing more than a "common bird" (fan niao). The character feng consists of two parts which are respectively fan and niao.