Why Twenty is my latest mobile gaming obsession | Ars Technica

The result is one of those games that quickly reaches that magical state of flow, living in a zone of focus that runs off of pure reflex and muscle memory, without much conscious thought outside of a quickly ascending count. It's the kind of game that latches itself in the back of your brain and the inside of your eyelids for quite a while after you finish a session—as I type this right now, every time I glance down at the keyboard I'm semi-consciously trying to figure out how to smash the keys together into more orderly pairs.