Slot machines used to take up entire casino floors with cabinets over 50 inches...

https://wiki-coast.win/index.php/Why_Do_Mobile_Slots_Need_Bigger_Buttons_Than_You_Expect%3F

Slot machines used to take up entire casino floors with cabinets over 50 inches tall. Now, these games have shrunk to fit comfortably on phone screens just 6 inches wide