What do spades, hearts, clubs and diamonds in cards mean?

There is a theory that four colors represent the four major industries of society at that time. Spades represent spears and soldiers; Plum blossoms represent clover flowers and symbolize agriculture; Square represents bricks used by craftsmen; The heart represents the heart and symbolizes the priest. Another saying later became more common. These four colors come from the design of ancient European divination tools. Among them, spades represent olive leaves and symbolize peace; Plum blossom is a four-leaf clover, which means good luck; The square is a diamond, symbolizing wealth; The heart shape symbolizes wisdom and love.