Online slots evolved from simple three-reel games to a diverse mix of styles....

https://thefiguremagazine.com/classic-reels-to-megaways-how-online-slots-became-more-varied/

Online slots evolved from simple three-reel games to a diverse mix of styles. You’ll find classic reels, themed video slots, and new formats like Megaways and Slingo. Many include bonus rounds and jackpots that add excitement