Signs and symbols are so ingrained in people’s minds that we often don’t even think about their origins. For example, the letters this very sentence is made of.
We have some more “bricks” for your picture of the world. The last symbol was especially surprising to us.
Suits are most likely stylized pictures of certain objects: spades are swords, hearts are goblets, clubs are rods or staffs, and diamonds are coins.
Nobody really knows why these symbols are used on cards. Playing cards came to Europe from China. It is possible that there these objects stood for different estates: the noble (rods), the clergy (goblets), the merchants (coins), and the military (swords).
Skull and bones
The skull (sometimes with bones) is not just a symbol of death but also a symbol of eternal life and revival because bones don’t decompose when a person dies. That’s why in Europe this sign can be seen on cemetery gates, icons, and paintings of famous artists.
The pirate symbol is not connected with this story. By the way, pirates didn’t have a common flag, and Black Jack was the sign of the pirate Edward England. The skull and bones symbol was popularized by Robert Louis Stevenson, the author of Treasure Island.