Cards, roulette wheels, and slot reels hold more than the promise of a game -...

https://varimail.com/articles/why-reels-became-the-default-way-to-show-slot-outcomes/

Cards, roulette wheels, and slot reels hold more than the promise of a game - they record changing tastes, craft, and chance. In San Francisco in 1895, a small workshop helped shape the slot machine