Slot machines used to fill entire casino floors with cabinets over 40 inches...

https://rowansnewthoughts.quantlynix.com/posts/what-did-mechanical-slot-machines-use-instead-of-circuit-boards

Slot machines used to fill entire casino floors with cabinets over 40 inches tall. Now, you can play those same games on your phone’s 6-inch screen anytime, anywhere