One night when I came home from work, a security guard came on patrol and suddenly shouted to me: Stop! What for? I just got off work.... Security guard: What are the colors of CMYK? Me: Cyan, magenta, yellow, black. Security: You can go now. I was surprised. Me: Why do you ask such a question? Security guard: I was still hanging around in the community late at night, looking bitter, either a thief or a designer.