How to make up a joke with 3 yuan?

Someone exchanged a forged seven-dollar bill for two three-dollar change! (Old version) After breakfast that day, I paid the bill and was pulled back by the beef noodle vendor. He said, you gave me counterfeit money, and I recognized it, but you drew it with a pencil. What is even more exasperating is that it is still 3 yuan! I said, isn't that because I'm lazy? I drew two less pictures and saved your change! (Degang Guo Edition)