The main relationship between poker and year, month and day: there are four quarters in a year, so there are four kinds of cards, and each quarter has thirteen weeks, so there are thirteen cards in each suit, and there are 365 days in a year, which is more than 52 weeks, so there are 52 cards plus a king, and there are 366 days in a leap year, which is more than two days in 52 weeks, so there are 52 cards plus two kings.