Each king in a deck of playing cards represents great king from history. Spades – King David, Clubs – Alexander the Great, Hearts – Charlemagne, Diamonds – Julius Caesar.

Each of the suits on a deck of cards represents the four major pillars of the economy in the middle ages: heart represented the Church, spades represented the military, clubs represented agriculture, and diamonds represented the merchant class.

Each king in a deck of playing cards represents a great king from history: Spades = David ; Clubs = Alexander the Great ; Hearts = Charlemagne ; Diamonds = Caesar

Estonian ID cards have a chip with public-private key pair used to sign documents and vote in elections via the internet. For their 2011 election, 24% of the votes were cast online.