Cards, roulette wheels and slot reels carry casino history in their design and...

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

Cards, roulette wheels and slot reels carry casino history in their design and mechanics. In San Francisco around 1895, a small workshop helped shape the slot machine. This article follows the objects to see how gambling became public entertainment.