Zhuque Street Magical Calculation

Chen Yanzhou, a failed scholar, was living in the capital penniless. Then he discovered that a line of words would float above everyone's heads. That's what they really want to say. White is harmless, red is deadly. He set up a Gua stall on Zhuque Street and relied on his eyes to earn a living. But on the first day, I saw something I shouldn't have seen - five big blood-red characters above a certain noble prince's head: "Get rid of the Seventh Prince." The secret cannot be revealed. It doesn't hurt to give a little away.